stephanie2

I'm having an intermittant problem with the automatic transmission on my
1993 Audi 90s. I've spent lots of cash but nobody can seem to fix my car.

I believe it is an electical problem:

When driving the tach. needle will swing wildly or
drop to zero RPMs. This is occaisionally followed by the transmission
down-shifting suddenly and searching for the right gear (very unnerving at
65 mph).
The transmission hasn't flipped out while in the manual range, gears 1-3 (of course I can't drive faster than about 50 mph in third).
Sometimes when I start the car the tach. needle stays at zero.

An independant mechanic replaced the RPM sensor but it didn't fix the
problem. The Audi dealers tell me there's nothing wrong with my car.

Does anybody know what the problem might be?

ARK

Did Audi dealer read the DTCs (Diagnostic Trouble Codes) from the transmission control module??

ARK

The RPM sensor on the engine sends a signal to the Fuel Injection ECM, which then sends the RPM signal to the Tach, cruise control, and Transmission Control Module (TCM). It sounds like an intermittant connection between the ECM RPM output signal, to the TCM. The TCM would probably store a DTC if the RPM signal is absent. Ask dealer to hook up the VAG scan computer, and see if any DTCs are stored in the TCM. Its pobably a loose wire / connector.

stephanie2

Thanks for your response, Tony. The Audi dealer told me that he didn't get any trouble codes from the engine. . . I don't know if that means he checked the transmission for codes too?

The independent mechanic replaced both the TPS and RPM sensors with no results. He wants to "tear it apart" to find the problem. Do you think this is a good idea?

Thanks,
Stephanie