Hey guys ever since I changed my exhaust about a year ago my Service Engine Soon light has been on. I have had numerous mechanics with numerous types of scanners (snap on etc) scan my car and can never find any trouble codes. They can use the scanner to turn the light off, but it comes back on in a few hours. Once on one scan it did report a bad O2 sensor, we changed that and the light still stays on. Any idea what I can do to get this light off? Is there anyway to just disconnect the light all togeather? I've also tried disconnecting the battery for a while, the light goes off.. but comes back on again within a few hours.

Thanks,
Jonathan

97 Z28 6speed

 

Do you have gutted converters? If so, there's your problem. Also, you do know you have 4 02 Sensors, right? Cant pick and choose with those babies. You could've changed out a good one. Try changing all02 Sensors if you dont have gutted cats. Good Luck and let us know how things go!

 

If you can look at the live data from the O2's with the engine running, you can determine which one is bad. It seems to me that if the MIL is lit there shoud be a code associated with it. I know thoses snap-on scanners are great and very reliable. I used one to find a bad O2 on a friends WS6, so try it again and see what you can find. But, if you do have gutted cats then that would be your problem, more that likely. I think it would make car run different also.

 

havent gutted the cats.. I know theres 4 o2's we changed the one it reported as being bad (bank 1 senor 2) but it could be another bad o2 ... Any way to just "rig" that thing to go away?

 

I'm sorry I don't have any advice for fixing your problem. But if there is a way to disable the SES light, I wouldnt recommend doing it. You need it to know when you may be throwing a code in the future.

 

When that SES light goes on a scan should show a code. Something is not right. What kind of catback did you put on. I run a P0400 with my setup all the time once I hit the highway and get into 5th or beyond. New EGR, solenoid and vacuum lines wouldn't make it go away. I just live with it.

 

I just put regular flowmaster, not cat back or anything. I've been living with it for a year, but now that im trying to trade it in for a newer z28 dealers are kinda suspicious when you assure them the SES light is on but nothings wrong

 

Well in that case just pull the bulb out. gotta pull the whole cluster though...

 

My SES light recently came on and it turned out to be my gas cap. I have been using a Stant locking gas cap for the past six years (original owner) and put the stock cap back on. 5 minutes later the SES light went out. who knows but, Its worth a try and caps are cheap.