Vectra C - CIM works well only when PCB heated up

[chupocro]

Hi all, my first post here.

I have Opel Vectra C 2.0 2002 (motor Y 20 DTH) and am trying to diagnose the problem with the CIM module for quite a while. The problem goes away when I heat up the CIM's module PCB (or just drive for a while) and I did locate the area where the PCB has to be heated up for the problem to go away. I've marked the area which has to be heated up in the pictures.

Before I describe the details I'd like to ask if anyone could help me with any information about:

- The CIM module main connector pinout. I could't find that data in TIS.
- A way to backup the firmware and the data (flash + EEPROM) from both MC68HC908AZ60 microcontrollers (no separate EEPROM chip on this version of CIM). I'd like to backup these in case I'll have to replace the processors.
- The right way of removing the ICs. I've been working with SMD for years but this PCB has some kind of conformal coating. I've been told it could be removed with Abro Paint Remover spray but seems as the ICs are glued at the bottom.
- Which task is performed by the CIM's fimware every exactly 45 seconds (I know that is a hard question but in case someone disassembled the firmware :-) ).

Detailed description:

When CIM module is cold one of the microcontrollers restarts every exactly 45 seconds and after the fourth restart the firmare disables the HIGH <--> LOW speed CAN interface.

When the microcontroller restarts the RPM and speed indicators drop to zero for a moment and there is a warning sound if the seat belt is not fastened as when the ignition is on for the first time and ESP + ABS lights blink for a moment. After the fourth restart (after 3 minutes) when HIGH to LOW speed CAN interface turns off the communication with the instrument table stops (since it is on the low speed CAN bus) all the indicators drop to zero and alternator + ABS warnings light up.

The error stored by CIM is "B1006 - CAN-Bus Low Speed Controller Circuit Malfunction".

All other modules store the error "U2139 - CAN-Bus No Communication with CIM (Steering Column Module)".

After 15 or 30 minutes of driving (depending on temperature), especially if heating is on, everything starts to work correctly.

After CIM module disables the HIGH to LOW speed CAN interface all other modules on the low speed CAN bus can still communicate between each other without errors. The "only" problem is after the fourth restart CIM doesn't anymore send the data towards the instrument table and it doesn't send the data about pressing the buttons on the steering wheel, pressing the horn and using the turn signal and wiper handles. This YouTube video shows exactly the same problem.

I checked the CAN signals with the oscilloscope and they are perfect.

I tried to heat up different areas of the PCB to locate the cause and seems as everything works well when I heat up the area where is TLE 6255 Single Wire CAN-Transceiver IC (which is used by the CIM for communication with the low speed CAN bus).

I am aware the ground planes might spread the heat to some other location and heat up some other element but at the moment I have to apply the least heat when heating the area where the TLE 6255 is - regardless of the side of the PCB I apply the heat to.

I reflowed both microcontrollers (just in case) and TLE 6255 but seems as it wasn't a dry solder joint on these ICs.

I will order a new TLE 6255 to see if the problem is that IC and I'll replace the 220 µF SMD capacitor above the TLE which is connected between +12 V going to TLE and GND.

The problem is I can't measure voltages with the ignition on because the PCB has to be inserted plugged into the key lock and the measuring points are on the other side.

In the meantime, I would be grateful for any information about the CIM (pinout, backing up the firmware, ...) and/or any advice about repairing it.