cossie

The speedometer of my 1990 C2 suddenly stopped working, consequently the tiptronic likewise failed. I can now only use it in D - the tip does not work even if the gear lever is engaged in Tip mode. In short only the D gauge lights work, the speedometer, tip shifter lights and the tip itself are not working.

Any tips on how to fix the problem?

Arrowhead

I am not sure what your problem is but the are 2 elec. cables that plug into the side of the trans. One goes to the speed pulse sensor. I would first check and clean the 2 plug connections. And of course the speedometer connection. Have you had any work done on the car lately?

cossie

this happened after i did an oil change and cleaned the ICV... anything near the ICV I may have accidentally hit that caused this?

Arrowhead

I do not suspect there is anything near the ICV that would cause your problems. The throttle valve potentionmeter does influence the tip ecu. Make sure all the elec. connectors are pluged in that area.

sundog

if the signal from the wheel speed sensor and speedometer don't match, then it won't go into TIP mode. I had a broken wheel speed sensor, and that did it. But that also made the ABS not work either.

Arrowhead

sundog, interesting. Is it a perticular wheel speed sensor or any, and did your speedometer stop working?

NineMeister

Likely that you have no speedo signal. The digital speedo signal is an output of the ABS ecu which is generated from the analogue signal of the front right wheel speed sensor. The ABS output is converted to the correct frequency waveform by a module in the main fuse board which looks like a relay, I can't remember the part number off hand. Hence if the speedo and tip are both malfunctioning but the ABS is working, it is likely that you have a failed frequency converter in the fuse board.

I should mention that the 1989 only 964 has a speed sensor on the gearbox, these cars drive the speedo directly from that gearbox sensor.