I was driving home from work today and the SES light went on again.. luckily I borrowed my friends auto Xray and i scanned it.. This is the fifth time it has gone off.. Only at night though.. I was driving home from work all nights.. One time i think it was raining out and it was about 6 pm... Anyway, i scanned it and there is "no trouble codes found" what the hell!!!??? Then when i clear it it goes away... Then it eventually comes back.. On the history codes it says code 32 EGR failure... I know about that.. that would trigger a code but no light.. What is going on??????? I have MAC headers.. uncoated, maybe they burned something? cant find anything though... SOME ONE PLEASE HELP ME!!!

 

That code will light your SES or MIL as GM calls it. Are you having any other problems? Check for plugged passages. Vacuum test the EGR diaphram.

 

The EGR has been blocked since before i can remember.. Thats not the problem.. Not having anyproblems.. Car runs great to me. except for the SES light.

 

Cant anyone help me??? This car is a 95 Z28 OBD1... No light for egr.

 

I'm confused by your post... you have an SES light, and when you scan it, there is a DTC 32 for "EGR system failure". And you don't have an EGR valve, so it is POSSIBLE for the OBD-I system to detect the absence of the valve, set the code and light the light. The OBD-I diagnostic is just not as sensitve as the OBD-II routine, but it does exist and in some cases will light the SES light.

Why do you say DTC will not set the SES light? Why do you feel the DTC 32 is only "stored" and not "active"?

 

The valve is still there.. I have a block off plate and then the EGR over it.. I have had the EGR block from the second i bought my car about a year and a half ago. Would a fuse do this?? When i clear the codes on the Auto Xray it goes away though.. it will eventually come back but not in the next 20 minutes... Puzzleing the crap out of me

 

Of course it won't come back in 20 minutes... it won't come back until the specific conditions are met that require the PCM to activate the EGR. Low load cruising is a common time for it to occur.

The fact you still have the valve doesn't avoid the code. DTC 32 is set when the PCM activates the valve and doesn't see a "blip" in the MAP that is expects to see. If you still have the valve, but flow is blocked by a plate, there is no way for the MAP sensor to see the EGR flow. That's DTC 32. Its not for the fuse. There is a seperate DTC code for the EGR solenoid, and that is the part that is controlled by the fuse.

Still confused.

 

It does happen when i cruising home from work not getting on the gas to much.. I see it pop it.. Im very confused