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Siemens MS43

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The Siemens MS43 engine control unit (ECU) uses an Infineon C167CR_SR CPU clocked at 24MHz in combination with a 4 megabit AMD AM29F400BB flash memory.

This ECU controls the BMW M54 inline six engine.

When looking at the cryptic item names this might help you: Siemens Keyword Translation

Memory Layout

The MS43 can be seperated into three major sections, first comes the bootloader, then the program code, and last the calibration data.

See this table for file locations:

Start End Section Size
00000 0FFFF Bootloader & UIF 64 kByte
10000 1FFFF Program Code 384 kByte
20000 2FFFF
30000 3FFFF
40000 4FFFF
50000 5FFFF
60000 6FFFF
70000 7FFFF Calibration Data 64 kByte


Bootloader Section

The bootloader code section is the most important section of the MS43 and doesnt have to be touched for at least 99% of all use cases.

This section is 64 kByte in size and contains the interrupt setups, input and output initializations, as well as immobilizer information and the UIF (user information fields).

The significant difference between the bootloader section and the others is, that it's only one time programmable under normal operation. That means once a byte has been changed from FF to another value, it is not changeable again.

Unlimited write access to the bootloader section can only be archieved through JMGarage Flasher and is ONLY needed for virginizing the ECU to pair it with a different EWS module or to alter the UIF without increasing the flashcounter.

Tip: The newest version of immobilizer and checksum delete will not need bootmode flashing.


Programm Code Section

All of the MS43 program code is located here.


Calibration Data Section

Checksums

The MS43 uses three CRC16 checksums that verifies the data integrity of the boot, program and calibration sections and two addition checksums that verifies the data integrity of the system monitoring (_mon) parameters. If any of the checksums are incorrect the ecu assumes that the data on flash has been corrupted and it won't allow the engine to start.

When correcting the checksum the addition checksums have to be corrected before the CRC16 checksums, as the addition checksums are located inside the CRC16 checksum areas.

The checksums are located at the following addresses:

CRC16 Location
Boot 0x3C24
Program 0x6FDE0
Calibration 0x73FE0
Addition Location
Program Part 1 0x6FDAE
Program Part 2 0x6FD80
Calibration Part 1 0x72FFC
Calibration Part 2 0x72FFE

Disabling Calibration Checksums

Note: It's not advised to disable the calibration checksums as the ecu looses the ability to verify the data integrity of the calibration data.

Disable CRC16 Checksum

To disable the CRC16 calibration checksum do the following.

Hexeditor
1. Set Word at 0x73FFE to 0xFFFF
2. Set Byte at 0x6FFB0 to 0xA8
3. Change the Byte in the table from 0x84 to 0x94
Firmware Location
430037 0x58999
430055 0x5B87D
430056 0x5B87F
430064 0x5FEB3
430066 0x63595
430069 0x63595

Disable Addition Checksum

To disable the addition calibration checksum use one of the following methods.

Tunerpro
1. Set lc_swi_cal_mon_cks to 165
Hexeditor
1. Set the Byte in the table to 0xA5
Firmware Location
430037 0x70CE3
430055 0x70D7C
430056 0x70D7E
430064 0x70DA0
430066 0x70E0A
430069 0x70E07

Variants Configuration Switches

As MS43 is used in many different chassis configurations there are quite a few configuration switches that enable or disable their corresponding features or change their behaviour.

Configuration brake light test switch logic variant (c_conf_bts)

  • 0: Signal high corresponds to 'brake actuated'
  • 1: Signal low corresponds to 'brake actuated'

Configuration exhaust system variant (c_conf_cat)

  • 0: Automatic learning of variants, single bank, with one control (pre cat) sensor or CATV variant (SA199)
  • 1: Automatic learning of variants, dual bank, with two control (pre cat) sensors or CATV variant (SA199)
  • 2: Single bank, 1 control (pre cat) sensor, 1 monitoring (post cat) sensor
  • 3: Dual bank, 2 control (pre cat) sensors, 2 monitoring (post cat) sensors
  • 4: Automatic learning, dual bank, with/without control (pre cat) sensors, with/without monitoring (post cat) sensors or CATV variant (SA199)

Configuration main switch cruise control variant (c_conf_cru_main_swi)

  • 0: main switch function active, main switch controlled over steering wheel button O/I
  • 1: main switch function inactive for Z3 usage, main switch enabled when ignition key voltage is present

Configuration DMTL module variant (c_conf_dmtl)

  • 0: DMTL module not present
  • 1: DMTL module present

Configuration ECF (Electrical Cooling Fan) variant (c_conf_ecf)

  • 0: ECF not present, function and diagnosis OFF
  • 1: ECF present, function and diagnosis ON

Configuration exhaust flap variant (c_conf_ef)

  • 0: Exhaust flap not present, function and diagnosis OFF
  • 1: Exhaust flap present, function and diagnosis ON

Configuration diagnostic lamp / MIL variant - two control sensors and two monitoring sensors (c_conf_mil)

  • 0: No control of error lamp, LV_MIL = 0
  • 1: Debounce after BMW error memory
  • 2: Debounce after OBDII error memory and all component errors after 2nd driving cycle
  • 3: Debounce after OBDII error memory and CS-component error, immediately

Configuration diagnostic lamp / MIL variant - two control sensors (c_conf_mil_eu2)

  • 0: No control of error lamp, LV_MIL = 0
  • 1: Debounce after BMW error memory
  • 2: Debounce after OBDII error memory and all component errors after 2nd driving cycle
  • 3: Debounce after OBDII error memory and CS-component error, immediately

Configuration exhaust gas temperatur sensor variant (c_conf_teg)

  • 0: Automatic learning of EGT sensors
  • 1: No EGT sensors
  • 2: Dual bank exhaust system with four EGT sensors

Configuration torque limit first gear variant (c_conf_tq_lim_gear)

  • 0: Torque limit not active
  • 1: Torque limit active (E53)

Configuration SAP (Secondary Air Pump) variant (c_conf_sap)

  • 0: Automatic learning of SAP configuration
  • 1: SAP not present
  • 2: SAP present without SAFM (Secondary Air Flow Meter)
  • 3: SAP present with SAFM (Secondary Air Flow Meter)

Mass Air Flow Reading

M54B30 MAF Scalar

The most important quantity for our engine management is the mass airflow sensor reading. Its the fundament of every other calculation.

MS43 still uses analog reading for the MAF so a 0-5V signal is expected. Its important to have a clean signal without interferences.

Initially BMW planned to meter the air entering the secondary air pump system as well and included an additional MAF sensor input.

The analog signals are converted to a MAF reading in kg/h by the following scalars.

  • id_maf_tab - MAF Sensor Scalar 1x256
  • id_saf_tab - Secondary Air MAF Sensor Scalar 1x256
  • id_maf_tab__v_maf_1__v_maf_2 - MAF Sensor Scalar 16x16
  • id_saf_tab__v_saf_1__v_saf_2 - Secondary Air MAF Sensor Scalar 16x16

An important note for the sensor definition tables is, that there is no configurable voltage scale, because of the internal lookup mechanism and they are not interpolated.

For better visualisation the voltage scale is only included in the 1x256 tables, the 16x16 tables are only numbered.

In case of a mass airflow sensor failure or malfunction detection there is a substitute value table that looks up a MAF substitute value.

This table is often mistakenly called "Alpha/N" table, but its important to tune this even when having a working MAF sensor. Some other load value rely on this table being as accurate as possible.

  • ip_maf_1_diag__n__tps_av - MAF diagnosis table used as a MAF substitute if there is a MAF Sensor error
    • X axis: throttle position sensor value (tps_av)
    • Y axis: engine speed (n)

For MAF signal plausibility checks there are two maximum values that define maximum allowed mass airflow in kg/h and maximum engine load in mg/stroke.

  • c_maf_max_diag - Maximum mass air flow diagnostic threshold
  • c_maf_mes_max_stat - Maximum threshold for usable air mass flow signal

For forced induction builds you want to raise these to each constants maximum.

Load Filtration

In MS43 we have two different load filtration models for injection/ignition load and VANOS load.

Note: The normal logging routine reports the unfiltered load value that will vary from the filtered loads especially in forced induction applications.

If you ever experience your engine running into a "lean-wall" when hitting positive manifold pressure chances are good that the load filtering was not adjusted for boost.

Injection Load

Intake Manifold Volume Model

The load filtering process for the ignition and injection load is used to account for changes in the engines volumetric efficiency due to the variable valve overlap induced by the VANOS.

First the ecu calculates the manifold absolute pressure (MAP) with the help of Clapeyrons ideal gas equation by taking the effective intake manifold volume (hPa), the engine speed and the current airflow reading from the MAF sensor into account.

The effective intake volume is different between increasing and decreasing load scenarios and is therefore split up into four different tables:

  • ip_vol_im__n__maf_mes - Effective intake manifold volume at increasing load during part load and full load
  • ip_vol_im_neg__n__maf_mes - Effective intake manifold volume at decreasing load during part load and full load
  • ip_vol_im_is__n__maf_mes - Effective intake manifold volume at increasing load during idle, trailing throttle and trailing throttle fuel cut-off
  • ip_vol_im_neg_is__n__maf_mes - Effective intake manifold volume at decreasing load during idle, trailing throttle and trailing throttle fuel cut-off

Obviously, the more accurate this model and the MAF sensor readings is, the more accurate the calculated manifold absolute pressure value will be that's used in the next step.

To convert the manifold pressure to a load value the ecu uses 8 lookup tables ip_maf_vo_[1-8]__map__n and a selection table ip_nr_ip_maf__vo that decides which of those tables will be used depending on the current valve overlap.

  • ip_nr_ip_maf__vo - Active _vo_ table for maf_ti signal filtering
  • ip_maf_vo_1__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_2__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_3__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_4__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_5__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_6__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_7__map__n - Valve overlap based MAF signal filtering for maf_ti
  • ip_maf_vo_8__map__n - Valve overlap based MAF signal filtering for maf_ti

Each of the ip_maf_vo_[1-8] tables defines out how many milligrams of air per stroke the engine is able to consume for a given engine rpm, manifold pressure and valve overlap.

As the current valve overlap will not always be exactly at the 8 different valve overlap breakpoints defined in the ip_nr_ip_maf table the ecu will interpolate the load value between the ip_maf_vo_[1-8] tables so for example if the current valve overlap is halfway between the ip_maf_vo_1 table and the ip_maf_vo_2 table then the ecu will combine half of the load value from the ip_maf_vo_1 table with half of the load value from the ip_maf_vo_2 table.

In stock form these tables are setup to support manifold pressures between 50hPa and 1250hPa which gives the ecu some headroom to compensate for outside ambient pressure. So if a turbo- or supercharger is added to the engine then the manifold pressure axis of these tables will need to be extended to allow the ecu to handle higher manifold pressures see Extending VO Tables For Forced Induction

VANOS Load

The VANOS load filtration is a simple weighting factor to blend between real measured load and the MAF substitude table.

Siemens MS43 Maf Substitute.png

Vanos Load Weighting Factor.png

The factor depends on unfiltered load and changes to completely rely on MAF substitute with rising load.

This is done to provide a stable load reading for the VANOS to prevent it from moving too much back and forth when the load is rapidly climbing.

  • ip_fac_maf_sub_ivvt__maf_sub_diag - Measured load weighting factor for maf_ivvt filtering
  • ip_maf_1_diag__n__tps_av - MAF diagnosis table used as a MAF substitute if there is a MAF Sensor error

To make real VANOS load as accurate as possible you can either increase the factor towards 1.0 or fine tune the MAF substitute table (the preferred way).

For that you have to datalog unfiltered load, accelerator pedal value and engine speed. A good side effect of this will be that the engine runs better with a defective MAF sensor.

Extending VO Tables For Forced Induction

When you install a turbo- or super charger the amount of air entering the cylinder will increase tremendously and the ecu will operate outside the range of the stock tables.

Since the ecu is not able to extrapolate values, you will never exceed ~823mg/str engine load with an M54B30 calibration because that's the highest value configured in the valve overlap tables.

To make the MAP calculation and VO compensation able to handle higher pressure values than 1250hPa we have to extrapolate said tables on our own.

You can take following values as a guidance that were proved working in several boosted applications or use our prepared an Excel sheet to extrapolate your own tables: File:Load Filtration Table Extrapolation.zip

Siemens MS43 Load Filtration Boosted.png

Please note that this is only an example, but logging showed a perfectly calculated MAP value that matched measured MAP under all circumstances.

After hundreds of kilometers of logging data, we never experienced a measured pressure of under ~150hPa so it can be considered safe to shift the tables and axis values up to clear the last row for expected pressure.

When doing a M50 manifold conversions it could be a good idea to take a look at the intake models in the Alpina B3S binary, the Alpina manifold is pretty similar to the M50 so the intake model values should be closer than the M54 intake models.

Injection

The fuel injection maps are based on engine load over engine speed and the lookup value is injection time in miliseconds.

The lambda sensors for closed loop operation are narrowband. Fuel trim learning only happens during closed loop operation, but the learned fuel trims do affect full throttle fueling as well.

There are a lot of blending, enrichment and enleanment factors involved to calculate the final injection time. The following tables are the most important ones.

  • ip_tipr_cst__tco - Pre cold start injection time basic value
  • ip_ti_cst__n__tco - Cranking injection time basic value

Without any active VANOS fault codes the engine interpolates between the cold and warm injection tables. There are individual tables for each cylinder bank.

  • ip_ti_tco_1_is_ivvt__n__maf - Cold engine injection time used during idle
  • ip_ti_tco_1_pl_ivvt_1__n__maf - Cold engine injection time used for bank 1 during part load
  • ip_ti_tco_1_pl_ivvt_2__n__maf - Cold engine injection time used for bank 2 during part load
  • ip_ti_tco_2_is_ivvt__n__maf - Warm engine injection time used during idle
  • ip_ti_tco_2_pl_ivvt_1__n__maf - Warm engine injection time used for bank 1 during part load
  • ip_ti_tco_2_pl_ivvt_2__n__maf - Warm engine injection time used for bank 2 during part load

Axis Values

  • X axis: filtered engine load for injection subsystem (maf_iga)
  • Y axis: engine speed (n)

A blending between cold and warm maps is accomplished by the following transitioning maps. A factor of 1.0 means full useage of cold maps and a factor of 0.0 means full useage of warm maps.

  • ip_fac_is_ivvt__tco__tco_st - Engine coolant temperature blending factor for transition from cold to warm during idle
  • ip_fac_pl_ivvt__tco__tco_st - Engine coolant temperature blending factor for transition from cold to warm during part and full load

Axis Values

  • X axis: engine coolant temperature at engine start (tco_st)
  • Y axis: current engine coolant temperature (tco)

The full load enrichment ip_ti_fl is a multiplier of the part load calculations and added to them respectively. Further explanation is located in the full load section.

If the ecu is in the "cat preparation"/CATV state i.e. there are no lambda sensors connected to the ecu then the part-load injection time will be leaned out by the ip_ti_cat_var__n__maf table.

Maximum Duty Cycle

Maximum Injection Time Calculator

The maximum duty cycle describes the maximum opening time for an injector at a specific engine speed.

The engine speed is really important here, because the faster the engine spins, the less time there is to inject fuel into the cylinders.

When tuning the engines injection tables, especially in the higher load areas, keep in mind that there are additional enrich- and enleanments applied to the specified injection time.

These adjustments require some headroom on top of that value to work correctly and can be life saving regarding engine health.

Often a maximum duty cycle of 90% is sufficient for the safety features and the injectors to work as intended. When going higher we advise to think about upgrading to a higher flowing set of injectors.

Full load enrichment should be included, since depending on the target lambda it enriches the mixture more than 10%.

To make things easier we include the following Excel sheet: File:Maximum Injection Time Calculator.zip

You can easily check your fuel tables with this calculator, just load the engine speed axis, the full load enrichment factor and your desired duty circle into the grey areas and compare the values.

Note: The table on the right shows the theorethical maximum. As long as your injection time stays below this, you are fine.

Aftermarket Injector Scaling

Changing the fuel injectors will be needed at some point when you change your engines aspiration to forced induction, therefore some constants and tables need to be adjusted.

To find a suitable baseline for your new injection tables you will have to calculate the volume flow difference between the stock and your new injectors.

By dividing the flow rate of the old injectors by the flow rate of the new ones at the same fuel pressure you end up with a scaling factor.

You can use the injection time multiplier of the MS43s application system that is able to adjust every single cylinder injection duration with a factor t_ti_as_[cyl].

Playing with these six constants is much easier than always changing all the injection tables.

Nevertheless, once you've found a suitable factor for your injectors, apply it to the fuel tables directly and return to factor 1.0, because the application system will NOT alter the injection time reported by the MS43s logging routine.

Additionally you must adjust the following injector specific values:

  • c_ti_min_iv - Minimum injection time
  • ip_ti_add_dly__vb - Injector dead time correction with battery voltage compensation

Go here for a list of suitable fuel injectors and their deadtimes.

The maps to scale are:

  • ip_tipr_cst__tco - Pre cold start injection time basic value
  • ip_ti_cst__n__tco - Cranking injection time basic value
  • ip_tib__n__maf - Basic injection time under VANOS fault condition
  • ip_ti_tco_1_is_ivvt__n__maf - Cold engine injection time used during idle
  • ip_ti_tco_1_pl_ivvt_1__n__maf - Cold engine injection time used for bank 1 during part load
  • ip_ti_tco_1_pl_ivvt_2__n__maf - Cold engine injection time used for bank 2 during part load
  • ip_ti_tco_2_is_ivvt__n__maf - Warm engine injection time used during idle
  • ip_ti_tco_2_pl_ivvt_1__n__maf - Warm engine injection time used for bank 1 during part load
  • ip_ti_tco_2_pl_ivvt_2__n__maf - Warm engine injection time used for bank 2 during part load
  • ip_ti_slow_wf_thd_min__tco - Cylinder wall rewetting
  • ip_ti_fast_wf_thd_min__tco - Cylinder wall rewetting

After getting your base values for all these maps, you should log your lambda integrator to fine tune and get it as close as possible to +/- 0.

To fine tune starting and after start behavior, you can play with the following maps.

  • ip_ti_cast__tia__tco - Initialized value for post-start enrichment factor (After start enrichment)
  • ip_ti_cr_cst__cyc__tco - Gradual reduction of fuel enrichment at engine start
  • ip_ti_cr_cast__cyc__tco - Gradual reduction of fuel enrichment after engine start

DO NOT scale them to your injector like previous fuel maps, because these are factors, not injector pulse width in milliseconds!

Tip-In Enrichment / Cylinder Rewetting

An injection model with a fast and a slow deactivation of the compensation injection amount is used for the compensation of the wall film amount stored in the intake ports. To reduce air ratio fluctuations because of the updating error in the air path, a further wall film compensation amount is calculated from the change of the throttle angle, which is effective shortly after triggering a load jump.

For the load-dependent wall film compensation, the total wall film difference amount and the wall film difference amount to be compensated with high dynamic response between two sampling steps is quickly determined from the injection time difference (load difference) and a total wall film factor. The wall film difference amount to be compensated with lower dynamic response is calculated from the difference between these two variables.

The wall film difference amount for compensation of the updating error results from the difference between the map values IP_TI_PVS__PVS__N resulting from a map point change. This injection amount is corrected depending on the coolant temperature.

  • ip_ti_pvs__pvs__n - PVS angle-dependent wall film amount
  • ip_ti_tco_pos_wf__n__tco - Total wall film amount factor on acceleration
  • ip_ti_tco_neg_wf__n__tco - Total wall film amount factor on deceleration

The best way to scale the wall film table is rev the car then let off and see what AFR instantly appears. The goal is to achieve lambda 1.0 or gasoline AFR 14.7.

If the value is too rich, you need to decrease the wall film amount table. If the value is too lean, you need increase the wall film amount table.

Applying 5% steps to the whole table ip_ti_pvs__pvs__n in either direction shows good results soon.

Correcting Fuel Consumption Gauge

When changing injectors you will discover that the fuel consumption reading on your cluster and other monitoring apps is off.

The table ip_fco_map_cor__pq_main_col handles injection value reporting towards the cluster over CAN bus.

For example: You've lowered your fueling tables by MULTIPLIYING them with 0.46, you must DIVIDE the mentioned table by 0.46 to correct fuel consumption readings.

Fine tuning should be made in the secret menu of your cluster (+- 25%). This is explained here under "Test 20" INFO: E46 Instrument Cluster Test

Upgraded Fuel Pumps

Under some circumstances like a forced induction conversion the OEM fuel pump can't deliver enough fuel to the engine and needs to be upgraded.

The MS43 has two time values (in seconds) for controlling the electronic fuel pump relay before starting and after stopping the engine:

  • c_t_efp_prev - Time the electronic fuel pump relay is enabled after ignition turned on
  • c_t_efp - Time delay to disable the electric fuel pump relay after ignition turned off

Slightly rising these values may eliminate starting issues.

Tip: Some aftermarket fuel pumps don't come with an integrated check valve end therefor let the fuel flow back into the tank once the engine is turned off.

If this is the case consider adding a check valve right after the pump to keep stock-like cranking behavior.

Ignition

The ECU uses many different ignition maps depending on the engine state, engine temperature and quality of fuel.

Main tables that are used during normal engine operation:

  • ip_iga_tco_1_is_ivvt__n__maf - Target ignition angle during idle. Cold engine
  • ip_iga_tco_1_pl_ivvt__n__maf - Target ignition angle during part and full load. Cold engine
  • ip_iga_tco_2_is_ivvt__n__maf - Target ignition angle during idle. Warm engine
  • ip_iga_ron_91_pl_ivvt__n__maf - Target ignition angle for RON91 during part and full load. Warm engine
  • ip_iga_ron_98_pl_ivvt__n__maf - Target ignition angle for RON98 during part and full load. Warm engine

Axis Values

  • X axis: filtered engine load for ignition subsystem (maf_iga)
  • Y axis: engine speed (n)


Starting with a cold engine the ECU uses ip_iga_tco_1_is_ivvt__n__maf tables for idle, ip_iga_tco_1_pl_ivvt__n__maf for part and full load to find the target ignition angle.

While warming up the ignition subsystem uses the same blending factor as the injection subsystem. (see Injection)

Reaching engine operating temperature, the target ignition setpoint changes to warm ignition maps ip_iga_tco_2_is_ivvt__n__maf for idle and ip_iga_ron_9* for part and full load.

The target ignition angle in part and full load will then be blended between the RON91 and RON98 tables based on an internal RON factor learned from detected knock.

Under all circumstances keep the RON91 table a lot safer than RON98 to give the ECU some room for regulation.

It's common that even an unmodified engine running on RON99 fuel will pull a few degrees of timing here. This shows the RON98 map on a standard car is quite good.


Catalyst heating "_CH_" in maps retards ignition during warm up.

Anti-jerk "_AJ_" retards ignition during rapid throttle opening to smooth out torque (can be removed by increasing c_tco_min_aj to 142.5C.

Reported to sometimes cause transitional knock on boosted engines, if so consider adjusting other tables designed for this (tra_knk).

Ignition Coil Variants

In September 2002 BMW updated the old 300g ignition coils used from M50-M54 to the newer pencil style coils. This change required an automatic learning process for all new hardware variants, starting with Index 04.

The detection was implemented in an easy way. If the EGT Sensor Post-Cat Bank 1 input (Pin X60002.12) is connected to terminal 87 (main relay output) then the MS43 switches to pencil coil mode.

That means, if you retrofit the newer pencil coils or go with the M56 valve cover, you also have to retrofit the jumper wire in X60002 and an Index 04 or newer MS43.

To make this easier you can simply copy all the _pc_ values to their _300_ pendands.

Pencil Coil Data

VANOS

VANOS Min/Max Values

VANOS stands for "VAriable NOckenwellenSteuerung" and translates to adjustable camshaft control.

This section contains information on how the dual VANOS system is actuated by the ECU and how to modify it. Both, intake and exhaust camshaft can be set independently in relation to the crankshaft.

The VANOS system uses one hall sensor each on the intake and on the exhaust camshaft. Each of the sensors scans a toothed wheel with two 180° phases.

The intake CAM sensor serves for cylinder bank detection in the case of pre injection, for synchronisation, engine speed source in the case of crankshaft sensor errors and for position control of the intake camshaft (CAM).

To ensure correct pre injection, the intake CAM sensor has been designed as a static sensor, i.e. detection of the toothed wheel phase is even possible at 0 rpm.

The exhaust CAM sensor serves for position control of the exhaust CAM. Since it is designed as a dynamic sensor, a minimum engine speed is required to enable phase detection.

The VANOS system uses engine oil pressure and solenoids to control a set of gears at the end of each camshaft. The goal of the VANOS is to optimize emissions, produce better torque at low engine speeds and have more top end power.

Even though the camshaft adjustment is limited to 40°CRK it can be used to compensate for different intakes, different camshafts and even forced induction application may be benefitting from perfectly tweaked VANOS setpoints.

The main maps used for VANOS control during IS, PL & FL engine states are:

Cold Engine

  • ip_cam_sp_tco_1_in_is__n__maf_ivvt - Intake camshaft setpoint during idle. Cold engine
  • ip_cam_sp_tco_1_ex_is__n__maf_ivvt - Exhaust camshaft setpoint during idle. Cold engine
  • ip_cam_sp_tco_1_in_pl__n__maf_ivvt - Intake camshaft setpoint during part load. Cold engine
  • ip_cam_sp_tco_1_ex_pl__n__maf_ivvt - Exhaust camshaft setpoint during part load. Cold engine
  • ip_cam_sp_tco_1_in_fl__n - Intake camshaft setpoint during full load. Cold engine
  • ip_cam_sp_tco_1_ex_fl__n - Exhaust camshaft setpoint during full load. Cold engine

Warm Engine

  • ip_cam_sp_tco_2_in_is__n__maf_ivvt - Intake camshaft setpoint during idle. Warm engine
  • ip_cam_sp_tco_2_ex_is__n__maf_ivvt - Exhaust camshaft setpoint during idle. Warm engine
  • ip_cam_sp_tco_2_in_pl__n__maf_ivvt - Intake camshaft setpoint during part load. Warm engine
  • ip_cam_sp_tco_2_ex_pl__n__maf_ivvt - Exhaust camshaft setpoint during part load. Warm engine
  • ip_cam_sp_tco_2_in_fl__n - Intake camshaft setpoint during full load. Warm engine
  • ip_cam_sp_tco_2_ex_fl__n - Exhaust camshaft setpoint during full load. Warm engine

Axis Values

  • X axis: filtered engine load for VANOS subsystem (maf_ivvt)
  • Y axis: engine speed (n)


A blending between cold and warm maps is accomplished by the following transitioning maps. A factor of 1.0 means full usage of cold maps and a factor of 0.0 means full usage of warm maps.

  • ip_fac_cam_sp_in_is__tco__tco_st - Engine coolant temperature blending factor for transition from cam_sp_tco1 to cam_sp_tco2 during idle. Intake camshaft
  • ip_fac_cam_sp_ex_is__tco__tco_st - Engine coolant temperature blending factor for transition from cam_sp_tco1 to cam_sp_tco2 during idle. Exhaust camshaft
  • ip_fac_cam_sp_in_pl__tco__tco_st - Engine coolant temperature blending factor for transition from cam_sp_tco1 to cam_sp_tco2 during part load. Intake camshaft
  • ip_fac_cam_sp_ex_pl__tco__tco_st - Engine coolant temperature blending factor for transition from cam_sp_tco1 to cam_sp_tco2 during part load. Exhaust camshaft

Axis description are:

  • X axis: engine coolant temperature at engine start (tco_st)
  • Y axis: current engine coolant temperature (tco)

Camshaft Paramters

Thankfully we have a very easy way to tune the ECU to different camshafts. If at all you only need very small changes in fueling afterwards. The rest will be taken care of by the intake and valve overlap model.

In the initial position of VANOS (maximum spread), the edges of the exhaust CAM sensor are positioned at CRK tooth number 18/78 + C_COR_CAM_EX_REF °CRK, and the edges of the intake CAM sensor at CRK tooth number 42/102 + C_COR_CAM_IN_REF °CRK.

Plausibility limits have been defined for the non-adapted CAM edges; exceeding of these limits will result in an CAM diagnostic error:

  • Plausible range of intake cam: CRK teeth 31 - 46 and CRK teeth 91 - 106.
  • Plausible range of exhaust cam: CRK teeth 14 - 26 and CRK teeth 74 - 86.

If you want to change cams between engines or even go with aftermarket cams, you can use the following values to calibrate them.

Intake Camshaft:

  • c_cam_op_in - Intake camshaft duration in degrees
  • c_cam_adj_rng_max_in - Intake camshaft maximum VANOS adjustment range
  • c_cam_ini_in - Initialization value for intake camshaft refence angle adaptation
  • c_cor_cam_in_ref - CRK-correction for intake camshaft edges (aka intake lobe centerline)

Exhaust Camshaft:

  • c_cam_op_ex - Exhaust camshaft duration in degrees
  • c_cam_adj_rng_max_ex - Exhaust camshaft maximum VANOS adjustment range
  • c_cam_ini_ex - Initialization value for exhaust camshaft refence angle adaptation
  • c_cor_cam_ex_ref - CRK-correction for exhaust camshaft edges (aka exhaust lobe centerline)

Please make sure that the VANOS setpoint tables explained in the section prior to this are calibrated accordingly to the camshaft values.

Note: The B30 intake camshaft does not only have more lift and longer opening but its also 6° more advanced to support the engine in higher engine speeds compared to all other M52TU or M54 intake camshafts. Observations showed that tilting the intake camshaft by those 6° already made an improvement for top end power.

As a rule of thumb you can calculate a valid VANOS setpoint area for your cam setup as following. (B30 intake values for ease of calculation)

  • Upper Limit: c_cam_ini_in/ex (126°)
  • Lower Limit: c_cam_ini_in/ex - c_cam_adj_rng_max_in/ex (126° - 40° = 86°)

Drive-By-Wire

This section contains information on how the Drive-By-Wire system is controlled by the DME and how it can be modified.

The accelerator pedal unit is different between manual and automatic / sequential transmission.

For the automatic and sequential gearboxes the unit contains a spring mechanism that feels like a switch when the pedal is pressed to imitate a kick-down switch.

Manual pedal value is ranging from 0-85°PVS, whilst the automatic and sequential pedal value reaches from 0-89°PVS with 103°PVS at kick-down.

Drivers Wish Tables

Tunerpro comparison of the ip_tps_sp_pvs and ip_isapwm_pvs table.

The Drive-By-Wire system is setup so that the ecu uses both the throttle valve and the idle control valve to control how much air is going into the engine.

  • ip_tps_sp_pvs is used by the ecu to decide how much it should open the throttle for a given pvs input.
  • ip_isapwm_pvs is used by the ecu to decide how much idle control valve duty cycle should be used for a given pvs input.

If we look at these tables side by side we can see that a stock ecu is setup to primarily use the idle control valve to control airflow when the pvs input is in the range between 0° and 15° and when the pvs input is higher the ecu will switch over to the throttle valve.

Drivers Wish Input Correction

To provide a smooth driving experience during part load the ecu actively controls how fast the drivers requested pvs input can increase.

ip_pvs_cor_max_rpl_[gear] is used by the ecu to decide if the drivers requested pvs input increase should be limited. The values in the table is the lower limit and the X-axis is the upper limit. If the drivers requested pvs input is between these values then the ecu will start limiting the pvs input increase.

If the following conditions are met then the ecu will not try to start limiting the pvs input increase:

  • The driver requested pvs input is decreasing.
  • The driver requested pvs input change gradient is larger than c_pvs_av_grd_max_rpl(59,99° pvs).
  • The clutch is pressed.
  • The driver requested pvs input is higher than c_pvs_cor_max_rpl(42,5° PVS)

When the ecu starts limiting the pvs input increase the pvs input will be increased by the value taken from ip_pvs_cor_rpl_lgrd_[gear] until the following conditions are met:

  • The limitation duration specified in ip_t_pvs_cor_rpl_[gear] has expired.
  • The driver requested pvs input change gradient is larger than c_pvs_av_grd_max_rpl(59,99° pvs).
  • The limited pvs input is larger than the driver requested pvs input.

If any of those conditions are met then the ecu will use the driver requested pvs input and will not start limiting the pvs input again until the time specified in c_t_dly_pvs_cor_rpl(0,2s) has elapsed.

To disable the drivers wish input correction function set either c_pvs_cor_max_rpl or c_pvs_av_grd_max_rpl to zero.

Throttle Request Correction

To provide a smooth driving experience during low throttle openings the ecu will control how fast the throttle setpoint can change depending on the current engine load.

ip_tps_req_ltc_min_[gear] is used by the ecu to decide if the throttle setpoint change should be limited. If the requested throttle setpoint is lower than the value in the table the throttle setpoint change will be limited.

If the following conditions are met then the ecu will not try to start limiting the throttle setpoint change:

  • The clutch is pressed.
  • The requested throttle setpoint is lower than c_tps_req_ltc_min(0.248° TPS)

When the ecu starts limiting the pvs input the throttle setpoint will be increased by the value taken from ip_tps_req_ltc_lgrd_[gear] until the following conditions are met:

  • The limitation duration specified in ip_t_tps_req_ltc_max_[gear] has expired.
  • The requested throttle setpoint is larger or equal to ip_tps_req_ltc_min_[gear].
  • The clutch is pressed.

If any of those conditions are met then the ecu will use the requested throttle setpoint and will not start limiting the throttle setpoint again until the time specified in c_t_dly_tps_req_ltc(0,85s) has elapsed.

The id_tps_req_ltc_gear_[gearbox] tables controls if the throttle request correction should be active depending on the current gear. To disable the throttle request correction function set the id_tps_req_ltc_gear_[gearbox] tables to zero.

Torque

During engine operation the ecu will try to estimate the current torque being produced by using several static torque models.

Torque Models:

  • ip_tqi_pvs__n__pvs - Indexed engine torque (PVS)
  • ip_tqi_maf__n__maf - Indexed engine torque (MAF)
  • ip_tqfr__n__maf - Frictional torque losses (MAF)

Torque Management

Based on the static models the ecu will ensure that the engine torque does not exceed the maximum allowed torque specified in ip_tq_max__n__pvs_cor_rpl.

As the torque models are setup for a stock engine they can produce unexpected reductions in power if the engine is modified, to disable the function set the torque values in ip_tq_max__n__pvs_cor_rpl to 65535 Nm.

The ECU also have a function to reduce torque in first gear (In production vehicles this was only used by the E53 X5).

The function will be activated if c_conf_tq_lim_gear is set to one and when active the ecu will ensure that the engine torque does not exceed c_tq_max_gear while in first gear.

Idlespeed

This section contains information on how the idle is controlled by the DME and how it can be modified.

MS43 has a few different tables that affect the nominal idle speed

  • ip_n_sp_is Nominal idle speed without additional load on the engine.
  • ip_dri_n_sp_is Nominal idle speed with drive engaged for AT gearbox.
  • ip_acin_n_sp_is Nominal idle speed with air conditioner switched on.
  • ip_dri_acin_n_sp_is Nominal idle speed with air conditioner switched on and drive engaged for AT gearbox.

The idle setpoint is modified from the nominal speed above by

  • ip_n_sp_add_cha_cdn_bat Nominal idle speed offset for battery charge state.
  • ip_n_sp_add_heat Nominal idle speed offset with catalyst heating function active.

In addition, the idle speed change rate can be changed with c_n_sp_lgrd_is.


Full Load Detection

Full load procedure shown in Tuner Pro
Full load injection converted to lambda and AFR
Full load state maximum timers

On MS43 we have an accelerator pedal angle (°PVS) dependent full load detection.

In full load operation (ES = FL) the engine will leave stoichiometric combustion and enriches the injection for preventing knock and maximum power production.

The whole lambda learning adaption from the O2 sensors is stopped while the engine operates in this state. Already learned long term fuel trims (LTFTs) will still be applied.

The engine will never enter full load state unless the engine speed is greater than c_n_min_fl which is the lower limit for FL detection. Setting this to 8160 rpm will disable full load state completely.

Additionally, either one of the two following conditions has to be fulfilled to activate full load detection.

  • c_vs_min_fl - Minimum vehicle speed for full load detection after engine start if c_tco_min_fl has not been exceeded.
  • c_tco_min_fl - Minimum coolant temperature for full load detection after engine start if c_vs_min_fl has not been exceeded.

Finally, once the accelerator pedal angles defined in the following tables are exceeded, the respective function will enter the full load state.

  • id_pvs_fl__n - Accelerator pedal position threshold for full load detection - Injection
  • id_pvs_fl_ivvt__n - Accelerator pedal position threshold for full load detection - VANOS
  • id_pvs_fl_vim__n_vim - Accelerator pedal position threshold for full load detection - DISA

In the full load state, the MS43 changes VANOS and DISA to seperate tables, but for injection it adds a specified amount of fuel.

This leaves us the following tables that actually alter injection, VANOS and DISA behaviour.

  • ip_ti_fl__n - Full load enrichment factor for nominal injection time
  • ip_cam_sp_tco_1_in_fl__n - Intake camshaft setpoint during full load with cold engine
  • ip_cam_sp_tco_1_ex_fl__n - Exhaust camshaft setpoint during full load with cold engine
  • ip_cam_sp_tco_2_in_fl__n - Intake camshaft setpoint during full load with warm engine
  • ip_cam_sp_tco_2_ex_fl__n - Exhaust camshaft setpoint during full load with warm engine
  • id_vim_fl__n_vim - Variable intake manifold (DISA) activation setpoints at full load

There is a gearbox dependant timer that configures the maximum spendable time in seconds at full load condition per gear.

If this timer has counted down to zero, the engine leaves full load operating state on its own. You will have to lift the pedal below the configured minimum position and re-enter full load.

  • id_t_max_fl__gear - Maximum time in the full load state. Manual transmission.
  • id_t_max_fl_at__gear - Maximum time in the full load state. Automatic transmission.

You can zero these tables to bypass the timer.

To extract every last bit of power out of your engine, there is c_pvs_fl_accin that handles the deactivation of the AC compressor when exceeding the configured value.

Tip: To make tuning at full load (and wide open throttle) operation easier, you can change the conversion factor of the ip_ti_fl__n table to display lambda or AFR depending on your preference.

This is only applicable if your part-load table is tuned to stoichiometric combustion (lambda 1.0).

Title Conversion Low Range High Range
ip_ti_fl__n (Lambda) 1-(0.0039058823*X-0.5) 0.500 1.500
ip_ti_fl__n (AFR Gas) 14.7-(14.7*(0.0039058823*X-0.5)) 7.409 22.050

Warning: Keep in mind, that all full load injection edits rely on a proper part load fueling table.

Lambda Regulation

MS43 has a cylinder bank selective lambda regulation that is utilizing one narrow band O2 sensor per cylinder bank. That means the ECU knows when a lean or rich condition occurs, but doesn't know HOW rich or lean it currently runs.

Due to this limitation the ECU continuously regulates the mixture to keep combustion exactly at lambda 1.0 (14.7 AFR / Stoichiometric) while in closed loop operating state.

Closed loop lambda regulation means that the O2 sensors or lambda probes provide feedback to the fuel injection routines which will then correct injection time accordingly.

Open loop means that the fuel injection time will solely depend on input quantities like air mass flow and ambient pressure without a feedback loop.


The MS43 has several requirements to be fulfilled to enter closed loop mode:

  • c_lam_n_min - Minimum engine speed to enable closed loop regulation
  • id_t_max_ls__tco_st - Minimum time after engine start to enable closed loop regulation
  • id_lam_tco_min__tco_st - Minimum coolant temperature after engine start to enable closed loop regulation

If every of these conditions is met, MS43 will enable closed loop feedback. Whilst active, there is a lower and upper limit to lean out or enrichen the air fuel mixture:

  • c_lam_min - Minimum lambda integrator value for leaning the mixture
  • c_lam_max - Maximum lambda integrator value for richening the mixture

Between these two values the ECU can regulate the air fuel mixture instantaneously. These are called lambda integrators or short time fuel trims (STFT).


Lambda Adaptation

Lambda Adaptation Scheme.png

The additive and multiplicative adaptation corrections are taken into account in the entire map for calculation of the injection time.

To avoid problems involving the mixture while the engine is not at operating temperature, the lambda adaptation values of TCO and their own values (determined with engine at service temperature) can be attenuated.

This is accomplished by weighting the multiplicative components with IP_TI_AD_FAC_FAC__TCO__TI_AD_FAC and the additive components with IP_TI_AD_ADD_FAC__TCO__TI_AD_ADD.

Main Conditions:

  • c_tco_ti_ad_min - Minimum coolant temperature for lambda adaptation
  • c_tia_ti_ad_max - Maximum intake air temperature for lambda adaptation
  • c_maf_ti_ad_max - Maximum air mass for lambda adaptation


Lambda Additive Corrections:

  • c_ti_ad_add_min - Minimum value of lambda adaptation additive factor
  • c_ti_ad_add_max - Maximum value of lambda adaptation additive factor
  • c_maf_ti_ad_add_max - Maximum air mass for additive lambda adaptation
  • c_n_ti_ad_add_max - Maximum engine speed for additive lambda adaptation

Lambda Multiplicative Corrections:

  • c_ti_ad_fac_min - Minimum value of lambda adaptation multiplicative factor
  • c_ti_ad_fac_max - Maximum value of lambda adaptation multiplicative factor
  • c_n_ti_ad_fac_min - Minimum engine speed for multiplicative lambda adaptation
  • c_maf_ti_ad_fac_min - Minimum air mass for multiplicative lambda adaptation
  • ip_maf_ti_ad_min__n - Minimum air mass for multiplicative lambda adaptation
  • ip_maf_ti_ad_max__n - Maximum air mass for multiplicative lambda adaptation

Diagnostic Trouble Codes (DTC)

During operation MS43 will perform a series of self diagnostic tests to ensure that everything is operating correctly.

To prevent an error from triggering too quickly the MS43 uses a debounce system where an error has to be detected a set number of times before the error can become active.

DTC To P-Code Translation

To translate the active DTCs to the equivalent OBD2 P code the ECU uses a set of variables c_dtc_[dtc name]_x that specifies the corresponding OBD2 P code.

The full list of DTCs and their corresponding OBD2 P code can be found here: Diagnostic Trouble Code Translation

Suppressing Diagnostic Trouble Codes

Not all DTCs can be suppressed but those who can be suppressed have an incrementation variable c_abc_inc_[dtc name] which defines how much the debounce counter should increment each time the error is detected and a threshold variable c_abc_max_[dtc name] which defines the maximum value for the debounce counter before the error is activated.

To suppress a DTC the corresponding c_abc_inc_[dtc name] variable needs to be set to zero. This prevents the debounce counter from incrementing which prevents the DTC from activating.

Note: Suppressing a DTC will not de-activate the functions associated with it so it's advised to correct the tune instead of suppressing any DTC.

Extra Features

This section describes extra functions or modification that where not intended by Siemens or BMW.

Engine Coolant Temperature Control

The M54 engine family is fitted with an electronic thermostat that the ECU can control to alter the engine coolant temperature.

By altering these values we can change how hot the engine will run in different conditions.

E-thermostat minimum conditions

  • c_tam_min_ect - Minimum ambient temperature threshold for e-thermostat activation
  • c_tia_min_ect - Minimum intake air temperature threshold for e-thermostat activation
  • c_toil_min_ect - Minimum oil temperature threshold for e-thermostat activation
  • c_tco_min_ect - Minimum coolant temperature threshold for full energization of the e-thermostat

E-thermostat maximum conditions

  • c_tia_max_ect - Maximum intake air temperature threshold. When exceeded target coolant temperature will be set to c_tco_sp_tia_max
  • c_tco_ex_max_ect - Maximum radiator outlet temperature threshold. When exceeded target coolant temperature will be set to c_tco_sp_tco_ex_max
  • c_toil_max_ect - Maximum oil temperature threshold. When exceeded target coolant temperature will be set to c_tco_sp_tia_max

E-thermostat target coolant temperature

  • c_tco_sp_toil_min - Target coolant temperature until the thresholds set by c_toil_min_ect, c_tam_min_ect, and c_tia_min_ect are exceeded.
  • c_tco_sp_tco_ex_max - Target coolant temperature if c_tco_ex_max_ect is exceeded
  • c_tco_sp_tia_max - Target coolant temperature if c_toil_max_ect or c_tia_max_ect are exceeded
  • c_tco_bol_ect - Target coolant temperature if an external low coolant temperature request has been received


E-thermostat target coolant temperatures maps

  • id_tco_sp_ect__n__maf_sub - Target coolant temperature when c_toil_min_ect, c_tam_min_ect, and c_tia_min_ect are exceeded - AC off
  • id_tco_sp_ect_acin__n__maf_sub - Target coolant temperature Target coolant temperature when c_toil_min_ect, c_tam_min_ect, and c_tia_min_ect are exceeded - AC on

E-thermostat regulations

  • ip_ectpwm_i__tco_dif - e-thermostat I component
  • ip_ectpwm_p__tco_dif - e-thermostat P component
  • id_ectpwm_add__n__tco_sp - Required e-thermostat duty cycle to achieve coolant temperature setpoint

PS : some of you may experience loss of power setting coolant temperature too low on M54B30. Seems that those engines likes higher temp for optimal run.

TunerPro depiction of Coolant Maps

Secondary Air Pump Removal

When removing the secondary air pump the ecu needs to be configured to ignore the removed sap equipment. To instruct the ecu that there is no secondary air pump installed set c_conf_sap to 1 and clear the "learned variants" adaptation in the ecu.

Lambda Sensor Configuration

Constant "c_conf_cat" has five different options which represent the ecu´s ability to work with different lambda sensor configurations.

Set the following values that suit you needs:

  • 0: Single bank with one pre-cat lambda sensor or cat-preparation (SA199)
  • 1: Dual bank with two pre-cat lambda sensors or cat-preparation (SA199)
  • 2: Single bank with one pre-cat lambda sensor and one post-cat lambda sensor
  • 3: Dual bank with two pre-cat lambda sensors and two post-cat lambda sensors
  • 4: Dual bank with two pre-cat lambda sensors and automatic learning of post-cat sensors or cat-preparation (SA199)

After changing c_conf_cat you need to unplug all lambda sensors you won't be using and then clear the "learned variants" adaptation in the ecu. This will instruct the ecu to re-learn which lambda sensor configuration it should be using.

For example if you are removing the post-cat lambda sensors in a dual bank setup you need to set "c_conf_cat" to "1", unplug both post-cat lambda sensors and then clear the "learned variants" adaptation.

MAF Sensor Scalar Adjustments

The standard MAF sensor map is a non-interpolated 16 x 16 lookup table, that can also be shown as 1 x 256 table. The 10 bit analog to digital conversion is reduced to 8 bits and 4 bits of each are used to lookup the MAF value.

There are differences in flow between the M54B22/M54B25 and M54B30 MAF sensors, as the diameter is different. Differences in cross sectional area would be expected to rescale the values, but the sensor is part of the tube and not easily modified.

Ford or Bosch slot type sensors are often used in high horse power blow through configurations for turbocharging which the BMW OEM sensors are not well suited for.

Engine load (mg/stroke) is proportional to airflow (kg/h) divided by RPM and is used to reference most of the important injection and ignition tables.

There is a factory airflow limit of 1024kg/h that can be doubled with a patch that has undergone extensive testing, but the maximum engine load is still limited to 1389mg/stroke.

A M54B30 pulls about 600mg/stroke in cold conditions with a maximum airflow of about 630kg/h.

Changes to MAF tables should be kept smooth and progressive. Fuel trims plotted against MAF voltage can be used to fine tune the closed loop areas.

  • id_maf_tab__v_maf_1__v_maf_2 - MAF sensor definition. 1x256
  • id_maf_tab - MAF sensor definition. 16x16

Engine Speed Limiter

The MS43 has two gear dependent engine speed limiters, a soft-limiter and a hard-limiter for each gearbox type (manual or automatic transmission).

The soft-limiter works by cutting single injectors based on fuel-cut pattern, whereas the hard-limiter immediately cuts off all cylinders.

  • id_n_max_at: soft-limiter for AT gearbox
  • id_n_max_mt: soft-limiter for MT gearbox
  • id_n_max_max_at: hard-limiter for AT gearbox
  • id_n_max_max_mt: hard-limiter for MT gearbox

In addition to that, you will want to raise id_n_max_vs_max_at or id_n_max_vs_max_mt slightly above the hard-limiter.

The Siemens MS43 receives the current vehicle speed (_vs) via CAN bus from the rear right speed sensor signal of the ABS control unit. This is new and differs from older chassis that got it from a sensor inside the differential.

In case the ECU doesn't get a valid vehicle speed signal, for example when you put an M54 engine in an older chassis, or strip out the ABS block for weight reasons, a third RPM limiter is applied:

  • c_n_max_vs_diag: RPM limiter in case of missing vehicle speed

For aggressive hard cut reduce the limiter hysteresis to:

  • c_n_max_hys 32 to 0 (This disables the soft-limiter)
  • c_n_max_hys_max 320 to 32

Vehicle Speed Limiter

The maximum allowed vehicle speed is dependent on the transmission type and operates in two stages.

The first stage consist of a soft limiter where the ecu will shut down cylinders to prevent the vehicle speed from increasing. The activation point of the soft limiter is defined by the following variables:

  • c_vs_max_at_1 - Maximum vehicle speed automatic transmission
  • c_vs_max_mt_1 - Maximum vehicle speed manual transmission


The second stage consist of a hard limiter where the ecu will shut down the fuel pump to prevent the vehicle speed from increasing. The activation point of the hard limiter is calculated by adding c_vs_max_add to the soft limiter threshold. ov_vs_max_max = c_vs_max_[at/mt]_1 + c_vs_max_add

  • c_vs_max_add - Additive fuel cut hard limit for vehicle speed


By maxing out c_vs_max_[at/mt]_1 and c_vs_max_add the vehicle speed limit can be increased to 287km/h.

To completely disable the vehicle speed limiter set c_n_min_vs_max to 8160rpm.

  • c_n_min_vs_max - Minimum engine speed for activation of vehicle speed limiter


There is also some additional vehicle speed limits that will override in different scenarios:

  • c_vs_max_toil_max - Maximum speed when exceeding the max. oil temperature (c_toil_max)
  • c_vs_max_amt - Maximum speed with an active ssg error

Safety Features

The following information need to be handled with care as you´re able to turn off safety features! This can lead to severe damage to your engine.

Catalyst Overheating Prevention

  • ip_maf_min_cop__n__iga_dif - MAF threshold for catalyst overheating prevention function
  • ip_maf_min_cop_ron__n__iga_dif - MAF threshold for catalyst overheating prevention function with bad fuel quality

To disable catalyst overheating prevention (COP) set ip_maf_min_cop__n__iga_dif and ip_maf_min_cop_ron__n__iga_dif to 1389mg/stroke.

CAT Heating

  • id_t_ch_ti_cat_var__tco_st - Duration after start to switch on the injection time correction for catalyst heating function with cat-preparation (c_conf_cat 0 or 1)
  • ip_t_ch_ti__tco_st__km_ctr - Duration after start to switch on the injection time correction for catalyst heating function
  • id_t_iga_ch_cat_var__tco_st - Duration after start to switch on the ignition angle intervention for catalyst heating function with cat-preparation (c_conf_cat 0 or 1)
  • ip_t_iga_ch__tco_st__km_ctr - Duration after start to switch on the ignition angle intervention for catalyst heating function

Set them to "0" to disable catalyst heating injection and ignition altering.

Misfire Detection

  • c_n_min_er: minimum engine speed for detection of misfire!
  • c_n_max_er: maximum engine speed for detection of misfire!

Knock Detection

The ECU samples the knock sensor voltage several times during the measurement window set by the id_knkwb_[0-5] and id_knkwe_[0-5] tables and the biggest reading is then selected for further processing to calculate the noise level for each cylinder nl_[0-5].

To determine the level 1 knock (light knock) threshold the nl_[0-5] data is multiplied with the ip_fac_knk_[0-5] tables and if the knock signal knks_[0-5] exceeds this threshold a level 1 knock event is signaled.

To determine the level 2 (heavy knock) knock threshold the level 1 knock threshold is multiplied by the id_fac_knks_thd__tia table.

If the multiplication factors in the ip_fac_knk_[0-5]/id_fac_knks_thd__tia tables is made smaller it will make the knock detection logic more sensitive and if they are made bigger the multiplication factor will make the knock detection logic less sensitive.

Ignition angle retards are specified in the following tables:

  • id_iga_dec_knk_1__n: ignition angle reduction based on knock stage1
  • id_iga_dec_knk_2__n: ignition angle reduction based on knock stage2

Special Functions

Please look here for the old 430056 functions that were published by Daniel.F back in 2015: Siemens_MS43_Old_Stuff

Here are some handy mods when going forced induction Forced_Induction_Upgrades



Differential Vehicle Speed Sensor Mod For E30/E34

If you want to use an MS43 in an older E30 or E34 chassis and keep the speed signal sensor inside your rear differential housing, you have to change the number of impulses needed for one kilometer.

  • c_vs_fac = Number of vehicle speed sensor pulses per kilometer

A suitable number for the E30,E34 and e36 diffs is c_vs_fac = "1096" ~ "1100" (Smaller value = Higher speed reading / Higher Value = Lower speed reading)

Note: This only affects ECU data acquisition and not the dashboard view, but its helpful for speed based parameters like LC config

Values can be fine tuned with a GPS based device to adjust for wheel/tire dimension differences

Unfortunately this low value will make the reading very unprecise. For a fix check out the MS43 Commuinity Patchlist.

Exhaust Pop Modifications

When tuning for exhaust pops there are two approaches that can be taken.

Toggleable exhaust pops

This approach disables the trailing throttle fuel cut by raising the minimum engine speed threshold for trailing throttle fuel cut to an engine speed that the engine can't reach, this will produce continuous exhaust pops as soon as the throttle is lifted.

As the MS43 has two separate tables for when the AC is on or off we can use that logic to for example only activate exhaust pops when the AC is on.

  • ip_n_min_puc__tco - Minimum engine speed for trailing throttle fuel cut activation with AC off
  • ip_n_min_accin_puc__tco - Minimum engine speed for trailing throttle fuel cut activation with AC on

To tune the intensity of the exhaust pops the following ignition tables can be used.

  • ip_iga_pu__n__tco - Target ignition angle in case of trailing throttle
  • ip_iga_puc__n__tco - Target ignition angle in case of trailing throttle fuel cut-off
  • ip_iga_accin_puc__n__tco - Target ignition angle in case of trailing throttle fuel cut-off with AC on
TunerPro depiction of toggled exhaust pops. This example should only be used as a starting point for further tuning.
Timered exhaust pops

This approach uses a built in timer function in the MS43 which delays the activation of the trailing throttle fuel cut by a set amount of time.

With this approach it's possible to achieve a set amount of pops before the trailing throttle fuel cut is activated.

  • c_t_puc_deacc_vs - Delay before activating trailing throttle fuel cut when car is stationary
  • ip_t_puc_deacc_1__n__maf_mmv - Delay before activating trailing throttle fuel cut. First gear
  • ip_t_puc_deacc_2__n__maf_mmv - Delay before activating trailing throttle fuel cut. Second gear
  • ip_t_puc_deacc_3__n__maf_mmv - Delay before activating trailing throttle fuel cut. Third gear
  • ip_t_puc_deacc_4__n__maf_mmv - Delay before activating trailing throttle fuel cut. Forth gear
  • ip_t_puc_deacc_5__n__maf_mmv - Delay before activating trailing throttle fuel cut. Fifth gear

To tune the intensity of the exhaust pops the same tables as the toggleable exhaust pops approach can be used.

TunerPro depiction of timered exhaust pops. This example should only be used as a starting point for further tuning.

Both approaches can also be combined in the following way to have short pops with AC off and continous pops when the AC is on.

TunerPro depiction of combined exhaust pops. This example should only be used as a starting point for further tuning.

In order to have pops when stopped, set the entire column in the first row to 7008 for id_n_hys_min_puc__vs__gear and id_n_hys_min_puc_dri__vs__gear.

Idle Control Valve Delete

TunerPro ICV Delete

Removing the idle control valve (ICV) / idle speed actuator (ISA) is possible due to the motorized throttle body the M54 engine uses.

Disconnect the idle control valve connector and either remove the idle control valve and plug the hole in the intake manifold (preferred) or use something to seal the idle control valve air tight.

If you want to machine a matching plug, use this template: ISA_Delete_Plug.pdf

The most important change that makes the ICV delete possible is the changes to the ip_pvs_isa_isapwm table. This table is used by the ecu to decide if any additional pvs input should be added to the drivers requested pvs input for a given idle control duty cycle.

In the stock setup the ecu will primarily try to use the idle control valve to alternate the air going into the engine during idle, but if the ecu encounters a scenario where it needs more air than what the idle control valve is capable of delivering at 100% duty cycle the ip_pvs_isa_isapwm table will help by translating the duty cycle to an additional pvs input that will be added to the drivers requested pvs input (which will be zero at idle as the driver isn't touching the throttle).

If take a look at the stock M54B30 ip_pvs_isa_isapwm table we will see that at 109% idle control duty cycle the table will add 17.5 degrees of pvs input and with an idle speed of 700 rpm the ip_tps_sp_pvs table would give us a throttle opening of 1.699 degrees.

If we then look at a scenario where ecu only needs a idle control duty cycle of 75% then the ip_pvs_isa_isapwm table will add 15 degrees of pvs input and with the same idle speed of 700 rpm the ip_tps_sp_pvs table would give us a throttle opening of 0 degrees which means the engine will only be receiving air from the idle control valve.

So when we remove the idle control valve we re-scale the ip_pvs_isa_isapwm table to emulate the idle control valve air flow with the help of the electronic throttle.

Copyable ICV Delete Tables M54B30 ONLY!.

The ip_pvs_isa_isapwm table values above are created for a M54B30 engine so the values may need to be modified to get a stable idle with a M54B22 or M54B25 engine as these engines have a smaller throttle body, a good starting point would be to increase the values with the opening area percentage difference between the M54B30 throttle body and the M54B22/M54B25 throttle body.

This modification modifies a monitoring table so the calibration addition checksum needs to be corrected or disabled after applying the changes. Check here for more information about checksums.


Lumpy Idle / Fake Race Camshafts

Basically whats happening when installing race camshafts is a huge increase in valve overlap. This means, intake and exhaust valves are open at the same time.

As M52TU and M54 have an adjustable camshaft system (VANOS) faking the rough idle sound of some serious camshafts pretty easy.

To get a similar sounding idle state you have to increase valve overlap time by adjusting the VANOS setpoints.

The idle speed VANOS setpoint are configurable in the following maps:

  • ip_cam_sp_tco_1_in_is__n__maf_iv - Intake camshaft setpoint during idle. Cold engine
  • ip_cam_sp_tco_1_ex_is__n__maf_iv - Exhaust camshaft setpoint during idle. Cold engine
  • ip_cam_sp_tco_2_in_is__n__maf_iv - Intake camshaft setpoint during idle. Warm engine
  • ip_cam_sp_tco_2_ex_is__n__maf_iv - Exhaust camshaft setpoint during idle. Warm engine


Additionally you have to raise the minimum engine speed threshold for the misfire detection c_n_min_er above your desired idle speed setpoint because this will otherwise stall the engine.

The biggest valve overlap will be achieved when using the lowest adjustable value on the intake side (80° respectively 86°) and the lowest adjustable value on the exhaust side (-80°)

TunerPro depiction of min allowed Vanos setpoints


A good starting point for further optimization could be:

TunerPro depiction of GhostCam mod

M Cluster LED Control

After swapping in an M3 cluster into a E46 or M5 cluster into E39, there is no more ecometer displaying the momentary fuel consumption, but a more useful oil temperature gauge.

Using this cluster and some additional code we can also control the LEDs around the RPM gauge to work similar to the E46 M3 and also manage shift light behavior.

Following maps are used:

  • id_icl_toil_led__n - LEDs used at the given oil temperature for the warmup light feature
  • ldpm_toil_led - Oil temperature axis to adjust the switch points of the led array for the warmup light feature
  • id_icl_led__n - LEDs used at the given engine speed for the shift light feature
  • ldpm_toil_led - Engine Speed axis to adjust the switch points of the led array for the shift light feature

Explanation for the decimal values used (M3):

  • 112 - all LEDs lit
  • 96 - 4500 and upwards
  • 80 - 5000 and upwards
  • 64 - 5500 and upwards
  • 48 - 6000 and upwards
  • 32 - 6500 and upwards
  • 16 - 7000 and upwards
  • 00 - 7500 lit
  • 02 - oil warning LED yellow
  • 04 - coolant warning LED

Explanation for the decimal values used (M5):

  • 64 - 4000 and upwards
  • 48 - 4500 and upwards
  • 32 - 5000 and upwards
  • 16 - 5500 and upwards
  • 00 - 6500 lit
  • 01 - oil warning LED yellow
  • 04 - coolant warning LED

Download the warmup and shift lights patch for TunerPro depending on your software version:

Use with 512kByte file only. Checksum correction required!

M3 Cluster warmuplight maps M3 Cluster shiftlight maps

Map Reduction

MS43 Map Reduction

The ecu is setup with cold(tco_1) and hot(tco_2) engine tables for the fuel, ignition and vanos functions which gives us a more fine grained control of the tuning throughout the engine operating range but it also leaves us with a lot of tables to keep track of.

If we want to reduce the number of tables that are used we can force the ecu into using the cold(tco_1) engine tables by setting the following cold/hot engine transition tables to "1.0":

  • ip_fac_is_ivvt
  • ip_fac_pl_ivvt
  • ip_fac_cam_sp_in_is
  • ip_fac_cam_sp_ex_is
  • ip_fac_cam_sp_in_pl
  • ip_fac_cam_sp_ex_pl

Doing this will leave us with the following maps during normal engine operation:

  • Injection
    • Idle Speed: ip_ti_tco_1_is_ivvt
    • Part Load: ip_ti_tco_1_pl_ivvt_1 & ip_ti_tco_1_pl_ivvt_2
  • Ignition
    • Idle Speed: ip_iga_tco_1_is_ivvt
    • Part / Full Load: ip_iga_tco_1_pl_ivvt
  • VANOS
    • Idle Speed: ip_cam_sp_tco_1_in_is & ip_cam_sp_tco_1_ex_is
    • Part Load: ip_cam_sp_tco_1_in_pl & ip_cam_sp_tco_1_ex_pl
    • Full Load: ip_cam_sp_tco_1_in_fl & ip_cam_sp_tco_1_ex_fl


ATTENTION: Be aware that the following tables will still be used if there is an active error in the ecu so don't forget to tune them as well.

  • ip_tib__n__maf
  • ip_igab_is__n__maf
  • ip_igab__n__maf



VANOS Tweak for little extra midrange power

Insert the following tables into the desired part-load map where you need the effect ( part-load cold / part-load warm / both).

VANOS Tweak maps in table form for copy and pasting into TunerPro M54B30 only
Exhaust cam setpoint part-load Intake cam setpoint part-load
-105.0 -105.0 -105.0 -104.6 -103.1 -97.5 -96.0 -96.8 -98.3 -104.3 -99.0 -99.0
-105.0 -104.6 -103.9 -102.0 -99.0 -96.0 -95.3 -96.4 -97.9 -103.9 -98.6 -98.6
-104.6 -103.9 -100.9 -97.5 -93.8 -92.6 -93.4 -94.9 -96.4 -101.6 -97.5 -97.5
-103.9 -102.4 -96.4 -92.6 -88.9 -88.1 -90.0 -91.5 -93.8 -97.1 -91.9 -91.9
-103.1 -101.6 -94.9 -91.1 -87.4 -86.6 -88.5 -90.4 -92.6 -96.0 -90.8 -90.8
-100.9 -98.6 -90.4 -87.0 -85.9 -85.1 -85.9 -88.5 -91.1 -95.6 -90.4 -90.4
-99.0 -96.4 -88.5 -85.9 -85.1 -84.8 -85.5 -88.9 -94.1 -97.5 -95.3 -95.3
-97.9 -95.3 -87.8 -85.9 -85.1 -85.1 -85.9 -91.9 -97.5 -100.9 -99.0 -99.0
-96.8 -94.5 -88.5 -86.6 -85.9 -96.0 -95.6 -95.6 -95.6 -95.6 -95.6 -97.5
-95.6 -94.1 -91.1 -88.5 -88.5 -99.8 -101.6 -101.6 -101.6 -101.6 -100.5 -101.3
-95.3 -93.8 -91.9 -90.4 -90.4 -101.3 -102.0 -102.0 -102.0 -102.0 -100.9 -101.6
-93.8 -93.0 -92.3 -92.3 -94.5 -102.4 -101.3 -101.3 -101.3 -101.3 -100.1 -101.3
-91.9 -91.5 -91.9 -92.3 -95.3 -105.8 -106.1 -106.1 -106.1 -106.1 -105.0 -102.8
-87.8 -88.5 -89.6 -91.1 -94.9 -106.1 -106.1 -106.1 -106.1 -106.1 -105.0 -103.1
-85.5 -87.0 -88.5 -90.0 -93.8 -106.1 -106.1 -106.1 -106.1 -106.1 -105.0 -103.1
-84.0 -85.9 -87.4 -88.9 -93.0 -106.1 -106.1 -106.1 -106.1 -106.1 -105.0 -103.1
126.00 126.00 125.63 124.88 123.00 118.88 113.25 106.50 105.00 104.25 108.00 108.00
126.00 126.00 125.25 124.50 122.63 118.50 112.88 106.50 105.00 104.25 105.00 105.00
126.00 125.63 124.88 124.13 122.25 118.13 112.50 105.75 104.25 103.50 100.13 100.13
125.63 124.88 123.75 122.63 120.38 115.88 110.25 103.88 99.75 98.63 91.50 91.50
125.25 124.50 123.38 121.88 119.25 114.75 109.50 102.75 98.63 97.50 90.75 90.75
124.50 123.38 122.25 120.38 117.38 112.50 107.25 101.25 97.50 96.75 90.75 90.75
123.38 122.25 120.75 118.88 114.38 107.63 102.00 98.25 97.13 96.38 90.38 90.38
122.63 121.13 120.00 117.75 112.13 103.50 99.38 97.50 96.75 96.38 91.50 91.50
115.50 113.63 111.75 109.50 104.25 93.75 99.38 98.25 94.50 94.13 94.13 94.13
113.25 111.75 110.25 107.25 100.50 91.88 100.88 99.75 94.88 94.50 94.50 94.50
112.13 110.25 108.00 104.63 94.50 90.38 101.25 100.50 97.50 97.50 97.50 97.50
110.63 105.38 99.75 95.25 89.63 90.75 105.75 105.00 101.63 100.50 100.50 100.50
109.88 104.25 97.50 92.25 109.50 110.25 109.50 110.25 108.75 108.75 108.75 108.75
108.75 103.88 99.38 94.88 115.50 118.13 118.13 118.13 117.75 117.75 117.75 117.75
108.38 106.50 104.25 101.25 118.50 126.00 126.00 126.00 126.00 126.00 122.25 122.25
108.38 108.75 108.00 106.50 122.25 126.00 126.00 126.00 126.00 126.00 126.00 126.00

DoCr VANOS Tweak

Explanation

For stock engine with stock exhaust and intake flow, above VANOS tune works best.

For a modded engine, or stock with free flowing exhaust and cold air intake, valve overlap can help increase volumetric efficiency at middle engine speeds (~4000rpm), which results in more power.

Taking as a base M54B30 engine with intake cam 126° for max, and 86° for min ; exhaust cam -105° for max and -80° for min

126° represents intake cam in its max retard form, and 86° in its max advance position

-105° represents exhaust cam in its max advance position, and -80° in its max retard stage

General rule for overlap :

  • Advancing both cams - more low end torque and less top end power
  • Retarding both cams - less low end torque and more top end power

Tip for full load VANOS table: Begin from low rpm with max number for your cam (intake 126° , exhaust -105°) and progressively reduce number until you reach 4000rpm and lowest cam number (intake 86,exhaust -80)

From 4000rpm upwards, use inverse technique, start to rise again numbers, progressively. (every engine responds different by exhaust config) Test combinations until you are happy.

Also, do changes for intake only, leave exhaust alone if you are on stock exhaust manifold.

note Theoretically, there is no risk of damaging the engine (valve hits piston) if you stay within specified range for your particular cams. (m54b30 intake 126/86 ,exhaust -105/-80)

Tuning For Turbocharged Applications

Here is a list of most of the maps that need to be changed when tuning for turbo setups.

It may also apply to supercharged setups, however there may be slight differences here and there because of how the power is delivered.

Fuel maps are not listed here because there is a section dedicated to scaling for aftermarket injectors.

If only a single value is listed and the map is a table, that means fill the entire table with that single value.

You should also consider Extending Load Filtration For Forced Induction, Aftermarket Injector Scaling, and Forced Induction Upgrades.

Map Value
c_abc_inc_vim 0
c_conf_cat 0
c_maf_max_diag 2048
ldpm_maf_8 35 75 125 175 250 325 400 450 550 700 950 1250
ldpm_maf_iga_1 50 75 125 175 250 325 400 500 600 700 950 1350
ldpm_maf_iga_2 50 75 100 125 175 250 300 325 400 500 600 700 850 1000 1150 1350
ldpm_maf_mes_1 76 125 272 376 523 1002
ldpm_map_1 100 200 300 600 900 1050 1250 2000
ldpm_n_11 600 1000 1200 1500 1600 2000 2500 3000 3500 3900 4100 4500 4800 5500 6300 7000
ldpm_n_14 320 600 900 1000 1200 1500 1600 2000 2250 2500 3000 3500 3900 4100 4500 4800 5100 5500 6300 7000
ldpm_n_4 600 1000 1200 1500 1600 2000 2500 3000 3500 3900 4100 4500 4800 5500 6300 7000
id_maf_tab Varies by maf
ip_ti_fl__n 0.016
ip_iga_ron_91_pl_ivvt__n__maf Decrease above 500mg/stk
ip_iga_ron_98_pl_ivvt__n__maf Decrease above 500mg/stk
ip_maf_min_cop__n__iga_dif 1389
ip_maf_min_cop_ron__n__iga_dif 1389
ip_ti_cop_nr_1_1__n__maf 0
ip_ti_cop_nr_1_2__n__maf 0
ip_ti_cop_nr_2_1__n__maf 0
ip_ti_cop_nr_2_2__n__maf 0
ip_ti_cop_nr_3_1__n__maf 0
ip_ti_cop_nr_3_2__n__maf 0
ip_ti_cop_nr_4_1__n__maf 0
ip_ti_cop_nr_4_2__n__maf 0
ip_ti_cop_nr_5_1__n__maf 0
ip_ti_cop_nr_5_2__n__maf 0