Audi RS4 MAF Sensor Conversion
A cheap alternative for the HPX PMAS MAF is the Audi RS4 B5 MAF sensor manufactured by Bosch and is able to measure upto 1800kg/h.
The MAF sensor module comes preinstalled in a 3.5 inch housing and has a 5 pin connector with the following pinout:
- Pin 1 - IAT sensor output (not used on MS42 or MS43)
- Pin 2 - voltage input 12V (red?)
- Pin 3 - common ground (black)
- Pin 4 - voltage input 5V (brown/white)
- Pin 5 - MAF sensor output (yellow)
The IAT output on pin 1 can be connected to an aftermarket logging device to monitor the intake air temperature before compression, or in case you leave it unconnected, make sure to seal the pin in the plug, to prevent the maf from corroding.
Pins 2, 3 and 5 should be self explaining, just connect them to the OEM MAF wires, or create a new 4-wire loom and run it to the cable distribution box located under the intake manifold.
Pin 4 needs a stable 5.00v supply voltage as this is the reference for the MAF output signal. This is very important for a precise reading!
The MS43 has two integrated 5V outputs, one for the electronic accelerator pedal and one for the electronic throttlebody. You can tap into the second supply right inside the cable distribution box.
By the way, this is pin 7 at the middle ECU connector (X60003) for the voltage U_DKG (brown/white, 0.5mm²). If anybody is concerned about the MAF drawing too much current, during operation it only needs 1,1mA
Now that you have the connection from the MAF to the ECU, the next part is applying the MAF hack (512k file) and editing the sensor definition (64k file)
In addition to that, you need to set "C_MAF_KGH_R_LS_MES_MAX" to 1800kg/h and C_MAF_MAX to 1389mg/str (the highest value possible for this constant).
- Audi RS4 MAF Sensor: Bosch partnumber 0 280 218 067 (new) or 0 986 280 219 (exchange)
- 5pin Connector: VAG part number 1J0973775A
- 90° protective cap: VAG part number 6X0971921C
The calibration data for this MAF sensor is available for copy and paste here: Sensor Scalings -> Audi RS4 MAF Sensor
The pinout is also available here : Electrical Connectors -> Audi RS4 MAF Sensor (0280218067)