OK, I have a '91 coupe w/ the auto tranny and the "S" light came on all by itself. Doesn't matter if I push the button on the gear selector, it still stays lit. I took a paper clip and tried to extract some codes from the OBD, but all that happened was the CEL came on and stayed on. When I pulled the paper clip out, the CEL light went out. No "S" light flashing, no D4 flashing, nothing. Any ideas, anyone??

 

anyone??

 

My guess is that something is wrong with the TCU (or the wiring).

You should reset the ECU and TCU by pulling the 7.5amp backup/radio fuse in the engine bay fuse box for a minute. Put fuse back in.

Drive the car until the S light returns, then try to short that blue two-pin connector under the passenger's kick panel to see if a real code has been stored. Let us know what you find.

Does the car drive poorly at all?

 

Thanks, PA. I will pull fuse/drive the car. I just bought the car last week and was waiting to get registration/insurance for it, so I haven't driven it much at all. But it drives fine (so far).