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HowTo: Convert M52TU Engine to MS43
The M52TU engine from BMW is almost the same as its successor, the M54 engine. Except for the throttle body and pedal it shares all sensors with MS43 powered M54.
It's not a complete plug & play operation to update the ECU from MS42 to MS43, but we try to make it as easy as possible with this guide.
Install Electronic Throttle Pedal
Parts List
- Mounting plate:
- LHD: 35 42 6 772 703
- RHD: 35 42 6 772 704
- Accelerator pedal:
- Automatic: 35 42 6 786 281
- Manual: 35 42 6 786 282
- Connector and cabling:
- Connector: BMW 61 13 8 383 300 (Tyco 1-967616-1)
- Terminals: 12x Tyco 5-963727-1 (MQS Quadlock 0.35mm²)
- Cable: 6m FLRy 0.35mm² (E46 chassis, others may vary)
Pinout
The electronic accelerator pedal (connector X11400) needs to be connected to MS43 (connector X60004) with six wires of about 1m in length for an LHD E46 chassis others may need longer wires due to the ECU box being on the right side or vice versa.
You can use any 0.35mm² cable since there is not much current used by the two potentiometers. We suggest using FLRy type wires with original colors from the table above.
| Pedal Side Pin | Signal Name | Color | ECU Side Pin |
|---|---|---|---|
| X11400.1 | M_FWG1 | brown/green | X60004.7 |
| X11400.2 | M_FWG2 | brown | X60004.12 |
| X11400.3 | U_FWG2 | yellow/green | X60004.14 |
| X11400.4 | A_FWG1 | white | X60004.8 |
| X11400.5 | U_FWG1 | yellow | X60004.9 |
| X11400.6 | A_FWG2 | white/green | X60004.13 |
Wiring Modification
For M52TU to work with MS43 you have two options for the wiring to fit.
Option 1: Adapt M52TU wiring harness to full DBW throttlebody
The easiest approach upgrading to MS43 is to make two little adapters, one for the throttlebody and another one for the signals goind to the cluster.
Option 2: Change Engine Wiring Loom To M54
X6011 - Engine Signals - 8 way black connector
| M54 Engine | Cable Color | MS42 Vehicle | Function |
|---|---|---|---|
| X6011.1 | black | following | Starter Signal |
| X6011.2 | green/brown | following | Terminal 15 |
| X6011.3 | brown/grey | X60004.11 | Oil Pressure Switch |
| X6011.4 | blue | X60004.13 | Charge Control Light |
| X6011.5 | grey/blue | X60004.21 | Oil Level Sensor |
| X6011.6 | black/yellow | X60004.02 | Engine Start Signal |
X6053 - Voltage Supply 8 way white connector
M52TU cars dont have seperated +12V lines for ignition coils and injection valves, so you have to connect pin 7 (red/yellow) with pin 2 (red/white/yellow).
