ABS Terminating resistor / CANBUS issue

[RickHaleParker]

I have tested the CAN wires many times, 60+-1 ohm always. I have the ABS module removed but a 120ohm resistor is placed between CAN H and CAN L pins. I am still unsure if the removed ABS module can cause such a communication fault? It would be so hard to believe...

Have you checked the CAN BUS wires for short to ground and shorts to a supply voltage line? Also an open can cause communication interference ( Signal reflection ). You might try cleaning the connectors on the ECM, ETM, TCM & SAS.

This might be a good time to add a signal tracer to your tool kit. It enables you to trace signals, find shorts and opens without disassembling the loom.

~$25.00 - $40.00 in the US. Much higher if you want to pay for a well known name brand.
In automotive these are often called: Short and Open Circuit Finder, Short finder ... ect.

[frmtaat]

It's been a while but i was woefully behind with work....

So basically i have tear the car apart, cleaned and checked every single cable, connection, metered everything for the correct voltage, impedance, especially the CAN cables against each other and against ground and supply voltage and everything was looked like fine...
I was sure that it is the ECU causing the issue due to some internal malfunction ( especially with ECU E003 and CEM E000 present) because as long as the ECM was out the communication was OK. I noticed however that plugging in the ECU but keeping the ETM unplugged keeps the canbus communication intact. I am going to test if ETM out and ECU in is good and indeed plugging in ETM brings up all the issues in the next couple of days (its kinda hard as the issue is intermittent).

But do you think that a malfunctioning ETM can cause such an interference in the canbus communication to force CEM to cease all communication for the entire system (CEM-E000)? It is really hard to believe.

Oh and Rick, i did bought a signal tracker, great tool, thanks so much for sharing and all the other info so far, really appreciate it!!!

[RickHaleParker]

But do you think that a malfunctioning ETM can cause such an interference in the canbus communication to force CEM to cease all communication for the entire system (CEM-E000)? It is really hard to believe.

Oh and Rick, i did bought a signal tracker, great tool, thanks so much for sharing and all the other info so far, really appreciate it!!!

A malfunctioning ETM could cause a lot of interference. It could be talking out of turn or just won't shut up. Ever been to a gathering where there was a motor mouth that talked nonstop. Virtually impossible for anybody else to have a conservation around them. A CAN bus is a party line. A motor mouth on a party line would wreck havoc on the ability of others on the party line to communicate.