TCM issues, code P0864

EVELYNC

MEMBER
2004 VOLKSWAGEN JETTA
2.0L
4 CYL
2WD
AUTOMATIC
166,015 MILES

Hello, I am a mechanic myself and need help regarding my car listed above. I am throwing a P0864 code for TCM communication circuit range/performance. The car will not shift out of first gear. I need to know what steps to take to officially diagnose that way I can order the parts I need. I am weak in electrical! Haha thanks!

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hello,

There is a park/neutral control relay that needs to be checked. Here is a guide to help us get started and the transmission wiring diagrams so you can see how the system works with a guide to show you how to test the wiring:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

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