EGS CAN timeout DME

[jdog1woof]

Hello folks
I have been scratching my head on this one and hoping someone else may have some new thinking to send my way. I have an amber gear illuminated (transmission fault) and check engine light. Going into the EGS module, you can see the code set “81- EGS CAN timeout: DME/DDE”. If you clear the code the transmission fault light goes out as does the engine light. The car can then drive with no issues. The transmission shifts perfectly in both modes, the engine and transmission are communicating (verified both directions with live data streaming between the modules). When the car is shut off and restarted the fault returns. I have so far inspected the wiring harness around both modules. Unplugged and cleaned terminals going to EGS (all looked clean already) checked fuses etc. does anyone have a diagnostic theory they would like to suggest? I am all ears

 

[NZ00Z3]

When you look at the fault code in the EGS, what is the related fault data? Are there any clues in that data.

 

[jdog1woof]

When you look at the fault code in the EGS, what is the related fault data? Are there any clues in that data.

Here is where I fall short a bit. I haven’t setup INPA yet as I don’t have a suitable laptop at the moment (just the work one) so all I have is this fault code. All live data from the foxwell looks solid. I have tried examining the communication between the modules (reading transmission data available through the DME and vis versa). It reliably sets this code at every startup (but once cleared doesn’t return until the next startup cycle)

 

[jdog1woof]

Following up to close this thread. After weeks of trying lots of different things to identify this timeout, reading literally every single technical manual on forums about diagnosing CAN timeout errors (it always came back to 'inspect the wiring and connectors' I was beginning to consider throwing in the towel. I was doing one last 'look at every wire on the car' pass when I noticed there were frayed wires at the connector for the thermostat plug. I found that a PO had done a less than awesome repair (guessing the wires were damaged doing coolant system repairs). I cut, soldered, and re wrapped these wires and who would have guessed- no more CAN timeout. So, I guess it reinforces the troubleshooting materials out there, if you are getting a timeout error, and you don't know of an obviously questionable module on the bus, start inspecting wires! (even if you suspect the offending wires may be unrelated to the module throwing the error). FWIW, I probably am now knowledgeable enough on this system to be dangerous. So if anyone needs help or advice, shoot me a PM!

 

[NZ00Z3]

Well done with your hard work and finding the problem.

 

[DrWong]

Well done for getting to the bottom of that and also for updating your thread, will no doubt be useful to others.!