'92 TPI, SES light stays on but only gives code 12 even when I know there are problems like the vss not even hooked up. Bought used and I don't know what is on the prom. Any suggestions what to check?

 

Have you had any problems with the fuel pump? There is a fuse and a fusible link near the battery, which is the ECM constant power (for storing codes), and the fuel pump. If there's a problem there, and the ECM is not getting constant power, all codes will be cleared when the car is shut off.

 

oops...should have said it's retro'd into a jeep. When I put it in seems like there were 2 wires labeled fuel pump. One was hot and the other didn't seem to do anything. So obviously hooked the hot to pump and just grounded the pump to frame and worked fine. I just went and found the unhooked wire and rechecked, it's not hot and not direct ground so I just hooked 12v to it and the SES light went out. Haven't tried to make it throw a code and not sure which pinout it is (I'd have to pull ECM). Does this sound correct?
thanks for the info