[Chris Souch]

Hello,

I have a ML55 2002 model RHD. I'm after the rpm feed that goes to the instrument cluster.

Anyone know the colour wire please?

Thank you

 

[43sqd]

There is no separate wire. The RPM signal comes over a CAN wire from the Traction Control Module.

 

[Chris Souch]

Thanks for this. I have a query though. I don't think the W163 has CAN bus as I have tried connecting the LPG ECU to pins 6 and 14 (CAN hi and low) to the diagnostic socket to keep the fuel trims correct. These pins are empty and I think a 2002 W163 does not have CAN.

 

[43sqd]

All ML's from day one had a CAN system.

From 1998-2000 they had CAN wires at the DLC #6 and #14.

From 2001+ they eliminated the CAN wires from the DLC and simply used the ECM to report CAN data, but you still have a CAN system. Below is a diagram of your CAN system. N3/10 U291 (ML55) shows the position of the CAN wires at the ECM.

Fuel trim data is read on a scanner through the ECM, so you don't need them at the DLC.

 

[DrX]

There is no separate wire. The RPM signal comes over a CAN wire from the Traction Control Module.

Without wishing to start an argument, I'd like to point out that the Vehicle Speed signal comes from the Traction Control module (using wheel RPM sensors), to give the speedometer reading, but I believe the OP was asking about the tachometer reading, which comes over the CAN from the ECM using the CKP sensor.