Hi everyone, I’m trying to track down a communication issue on my truck and could use some help locating the exact point of failure.
I believe I have an open or bad connection on the TCM wiring. I already checked continuity from TCM pins 6 and 7 to the OBD2 connector pins 6 and 14, and there is no continuity at all the meter shows infinite resistance / no connection. I tested with the TCM, ECM, BCM, and ABS pump disconnected from the circuit.
I also found that X109 is supposed to be involved with the CAN High and CAN Low circuits, but when I tried to check continuity from the ECM and TCM to X109, I couldn’t get continuity there either. At this point, I’m not 100% sure X109 is the correct connector for the section I need to diagnose.
What I’m trying to do is isolate the open by checking from the TCM connector to the next connector in the circuit, so I can narrow down exactly where the break is and hopefully repair the connection.
I’m still learning this stuff and doing my best with some DIY experience, so I’d really appreciate any guidance on which connector I should trace from the TCM to next, and how to localize the open more efficiently.
Thanks a lot in advance for any help.
I didn't specify the year, 2009 extended cab