Corsa 1.3CDTi Z13DTJ 2008 - Approach to multiple CAN coms problems #
Posted by Nick Bell on March 23, 2015, 9:28 pm
Year of Manufacture *: 2008 ( Optional ) Engine Code or CC: Z13DTJ
Hi, Just come back to diagnostics after 8 year sabbatical so I'm still playing catch-up.
A local garage had recovered this, I think due to no-start, found the ECU sitting in water, sent it away for repair. The vehicle now starts. When I arrived it had multiple Canbus communication errors for, just about, every module. I didn't have any problems communicating with them. Scoped Canbus signal at the EOBD socket and it appeared absolutely fine. Got as far as continuity checks from eobd socket, of Canbus to ECU and ABS with no apparent problems. I chose these modules as there was an ECU fault code as well relating to no comms. with ABS. I then cleared all the fault codes and took for a quick test drive around the bumpy industrial estate. Then I found many of the comms. codes had disappeared, but still no comms. between ABS and ECU, among others. I've now got a full wiring diagram, and a Canbus block diagram.
Not after the proverbial magic bullet (would be great to get one) but would like your views on the way forward. It seems as if disconnecting the battery before doing continuity checks reset something (BCM?) and reduced a lot of the comms. errors.
I've read that the BCM can become corrupted if the battery is flat and/or the car is bump-started. Both may have happened. Also will investigate interference from alternator.
Summary of last errors; ECU P0650-70 Canbus - no comms. BCM or CIM U2107-00 Canbus - no comms. BCM or IPC U2108-00 Canbus - no comms. ABS
ABS No faults
EPS C0000-08 VSS multifunction C044A-08 No RPM
BCM U2108-00 Canbus - no comms. with ABS
After test drive just read codes from the above modules, and will be checking continuity to BCM and EPS as well tomorrow, along with wiggle test etc.. I realise some of the above codes may be a different issue and therefore not relevant.
Do the different modules i.e. ECU and ABS, communicate with each other, or are all relevant messages arbitrated by one module, BCM for example, and dished out as required?
Any thoughts welcome...
Nick
Re: Corsa 1.3CDTi-approach to multiple Canbus comms. problems
Had a Meriva with similar problem and if I remember correctly the ECU was on the end of the CAN chain and then the ABS was next, My issue was between the ABS and Engine ECU.
Mark
Re: Corsa 1.3CDTi-approach to multiple Canbus comms. problems
Thank you Tony, Mark and Lee for your responses. Yes, I think I do need to retire after that one.
Well, went back again. Seemed to spend too long actually locating modules but...cleaned (that is, sprayed with contact cleaner) EPS (Electronic Power Steering) and Instr. Panel/Body Electrical connectors. Cleared remaining fault codes and drove around the estate again. It remained clear of codes so left it for the garage to test. I forgot to scope the alternator output due to being overwhelmed by feeling of euphoria and elation at being code free!!
It did raise a number of still unanswered questions. According to the block diagram the Canbus (hi-speed) 'chain', as seen from the diag. socket, was through the BCM (called the instrument panel/body electrical), through the EPS (power steering), then some modules hanging off the bus on 'stubs', then through the ABS, with the ECM at the end. As I had continuity from the diag. socket through to the ECM, and a proper waveform at the socket, it seemed all the wiring was intact! I still don't know if modules 'talk' directly between themselves, or if the BCM acts as the mail-room and gathers and re-directs messages between modules.
I left the car error free, and I haven't heard from the garage since so perhaps it's a fix. I guess I'll know for sure when I get paid!!