Hello everyone,
I am working on an Audi S6 4F / C6 with the 5.2 V10 engine and dual Bosch MED9.1 engine control units.
ECU part number: 4F1 910 552 C
The car uses a Master/Slave ECU setup:
J623 = Engine Control Module / Master ECU / address 01
J624 = Engine Control Module 2 / Slave ECU / address 11
The problem is that the ECU which should be the Master is detected as Slave / Engine Electronics 2. I can communicate with it, so power supply and CAN communication seem to be present, but it appears under address 11 instead of address 01.
Current DTCs in Engine Electronics 2:
U0100:08 / 9408:008
No communication with Engine Control Module
U0002:08 / 9154:008
Powertrain Data Bus - no communication / implausible signal
P1924:08 / 06436:008
Controller Pin Coding / Steuergerätpincodierung - implausible signal
From what I found, on Audi vehicles with two engine ECUs, the Master/Slave role is determined by a pin-coding / voltage-coding input. Apparently, if the coding pin has +12 V, the ECU should become Master / J623. If the pin is grounded or not supplied correctly, it is detected as Slave / J624.
CAN lines have been checked and they seem to be OK.
According to the wiring diagram, the normal CAN lines are:
J623 T94a/67 and T94a/68
J624 T94b/67 and T94b/68
There is also a separate ECU-to-ECU communication pair:
J623 T94a/89 → J624 T94b/90
J623 T94a/90 → J624 T94b/89
I am trying to find the correct pin-coding input on the MED9.1.1 ECU connector which tells the ECU whether it should work as Master or Slave.
Does anyone know which pin on the 94-pin connector is responsible for Master/Slave pin coding on Audi S6 4F / C6 V10 MED9.1.1 with ECU part number 4F1 910 552 C?
Or does anyone have the exact wiring diagram section where the Steuergerätpincodierung / Codierpin / voltage coding input for J623 and J624 is shown?
I would appreciate any help or confirmation before applying +12 V to any pin.
Thank you in advance.