I have a 1994 pontiac trans am and my SES light keeps coming on for a while but then turns off. I have tried to test it and when I put the tested in the harness the electric fans turn on and the SES light flashes WAY too fast to read it. My electric fans keep on turning on driving around even when it isn't hot. What could be the problem?

 

You can only do the "jumper" trick if you have a 93 f-bod. 94 and up you have to use a diagnostic scanner of some kind.

 

If it comes and goes, a good bet it is EGR related. Your fans will come on when the SES does, that's normal. As stated, you will need a scan tool to tell you what the code really is.

 

if i blocked my egr tube on the back of the manifold when i did my headers, would that cause the ses to come on? i havent had the egr programmed out yet.

 

OBD-I is usually not as sensitive as far as the EGR goes and it takes a certain amount of time driving in certain conditions to set it off. If you don't get the SES, don't sweat it.

 

well, just as you said it, my ses went off. since the computer will store this code, will it hurt performance? should i just clear the codes before going to the strip?

 

"Stored" codes don't cause the PCM to make any changes. Its just "stored" so you can retrieve it in the near future. Eventually, the codes will clear themselve from memory, but they don't affect anyhting being stored there.

If you "clear" the codes by pulling the PCM power, you will also be clearing the long term fuel corrections, and that might affect performance.

 

I have the intermitten SES light and I also thought it was the EGR. Turns out my AIR pump was seized up and that was causing the issue. I would be off when the car was started but then turn on after I drove for awhile. Turn off when I was sitting at a stoplight. Then come back on as I started to go. Haven't resolved it yet, but I'm just getting it tuned out and removing it from the car when I do the LT install.

 

When the SES light comes on the car kinda feels like it stumbles and I also noticed that today it made some loud pinging a couple of times. What different things could cause this other than the 02 sensor? I mean things that will trip the computer code too.

 

You really need to find out the code for the SES. Again, it could be the EGR, since one of it's functions is to lower combustion temperatures. Too high combustion temps could cause detonation (pinging).

 

The light never stays on. Everytime I go and get it tested it isn't on but as soon as I leave the damn thing pops back on for a bit.

 

But the code is stored, even if the light isn't on. ??????

What are they trying to scan it with?