Hello all, I picked up a 1990 964 C4 a month or so ago. The car needed some TLC but overall its a pretty good little 964 to knock around in.
The folks I bought it from mentioned the AWD light was on but they were able to get it to go off by replacing one of the accelormeters. When I received the car it was back on. I also notice a bunch of the warning lights were not coming on. So after playing around with the bulbs it was lighting up like a Christmas tree. I was able to resolve everything pretty easy but I just cant seem to get the AWD/ABS lights to go off.
I have gone through the below list of trouble shooting so I'm hoping someone may have another idea of what to try next.
Some info about the driving characteristics:
Before I did anything to the car the warning lights would come on almost instantaneously once I got over about 3 mph. Now,after doing the below, I can almost get out of my neighborhood about a 100yards but staying under 20mph. When I stop at the stop sign I can always feel the brake pedal give a bit...still no warning lights. after accelerating once I get up to about 20-25mph the AWD warning light goes off followed by the ABS about 5 seconds later. The brakes only settle as mentioned above that one time. Hopefully that all gives some clues as to what the issue might be:
Things I've tried:
ABS/PDAS
*Soldered Clock Cold Solder Joints - did this which resolved airbag/seatbelt lights
*Front boot crash sensor connectors-Cleaned contacts
*Replaced both accelerometers with newer solid state version
*Cleaned all 4 wheel sensors
*Relays-Replaced ABS, Brake booster, and fuel pump relays whith new
* Alternator - tested alternator and it was fine
*Check battery voltage -battery tested over 12 volts
* Checked PDAS control unit connection and cleaned connections
* Check pressure switch seal-no leaks detected
*checked and cleaned Ground wire behind pressure switch plug-
*Adjusted brake fluid reservoir level
*Checked ABS power connection at battery and cleaned
Any advice is greatly appreciated!! Thanks
Pic for fun...
