https://www.thirdgen.org/techbb2/sho...hreadid=159694


thanks

 

Well, unless the check engine light comes on when the engine is running all you will get when jumping the ALDL is code 12.

 

i do get the ses light on every now and then but it never really stays on long and there is no pattern to it...

the fu(ker just comes on and off at random

 

Confucious,

If the MIL lights, you have an error. If the battery power to the ECM is not interrupted, the code will be retained for the next 50 engine operating cycles. If all you get when you scan is a '12', you may have a problem with missing distributor reference pulses while running. That is exactly what a '12' is all about. If that's the case, you should be looking closely at distributor wiring, the HEI module, pickup coil and reluctor, and the ECM buffer module and wiring.

 

I have found that a check eng light that comes on and turns off by itself is usually an EGR code, and if the light isn't on for more than 15 seconds or so it would never set the code in the computer.
So far the EGR code is the only one I have encountered that will turn the light on, then off without turning the key off. It is caused by 1) a partially blocked EGR system 2) a bad connection in the diagnostic switch wiring or 3) a flakey diagnostic switch.