6 months ago my "Engine Check" light came on and the diagnostic message was the "Speed Sensor" in my Transmission Control Module (TCM) is sporadic. I drive a 2004 A4 CVT.

I went to a mechanic and he said you cannot replace the "Speed Sensor" chip alone but it has to be the whole TCM. The cost is $1400 for the part plus labor (approx. $1700).

Although, the "Engine Check" light is still on, I am planning to ignore the problem as I don't hear or feel any problems, however I wanted to ask whether others thought I am underestimating the potential damage that could happen if left unrepaired ?

 

Check the web for places that repair modules, from ECU to TCM, and even airbag modules. Also there is little labor to remove/replace the TCM.
If you have the exact code from a Vag-com, then Google is your friend!

 

I've been driving my '04 A4 for over 20k miles with the same code reading!No problem.

 

Unfortunately that would cause the car to fail the Biennial smog check here in California.