Ok my code puller says that I have a code 12 and a code 32. I know that code 32 is EGR, so I think I'll just replace it. But code 12 is something I don't know. The book I have says something about no reference signal to the ECM. Could someone fill me in on how to go about correcting this.

The SES light only comes on when I'm cruzin on the highway for like 10 minutes at a constant speed. Then my gas mileage goes way down.

 

Code 12 is normal. It is supposed to be there. Code 32 is EGR. Sounds like it is not working probably. I would try to do a vacuum test on it to make sure it is still good.

 

yep the EGR was bad. Replaced it and performed the same driving as when it used to come on and never did so I"m glad thats fixed. Thanks for the heads up on the code 12.

 

Well looks like the SES light came on again. Code reader says code 32, EGR. Well I don't know what to do since it is new. I quess I will go over all the vacum lines sometime this weekend.

 

Did you disconnect the battery for a few minutes to clear the codes? If you did, then it could also either be the EGR solenoid is bad, or you may have a leak in any of the hoses.

 

When I started modding my exhaust I started geting code 32. I put a new EGR on but never did get the code to go away. I think I didn't have enough back pressure to make the EGR function correctly. When the EGR is activated by the ECM it looks for the MAP to change slightly as a result. If it doesn't it assumes that the EGR is not working and throws code 32. Also I have heard that some of the non GM replacement EGR valves aren't close enough in flow and throw codes as a result. A friend of mine had that happen on a pickup. When he replaced the after market EGR valve with a GM piece the SES light went away for good.

 

I wish the TBI system was flexible enough to handle small mods without needing a new chip but thats a defferent thread.

I'm gonna check all the hoses tomarrow anway eventhough I replaced them all not to long ago and since I can't remeber when the light started coming on with whatever mod made it come on. Its a mystery till I get a chip with it turned off.