Service Engine Soon Light Went Off...

[Hicompression]

Really weird...the service engine light lit up a couple of days ago. I drove the car stop and go for about 15 miles. About the third engine start it went out and hasn't come back on since. I checked the owner's manual and it stated this light signifies something may be wrong with the emission system...ie: loose gas cap, converters, etc. I'm running MIL eliminators with the catted Bassani X. The only thing I can come up with is that I drive the car about 1x a week in this 100+ degree Texas weather. Maybe there was pressure build-up in the gas tank??? Any other ideas??? WTF? :wtf:

[Waltman]

Weird indeed, shouldn't happen at all. My tech service guy told me that any messing around with the cat system (replacing with after market stuff) will void your warranty. Did the light come up BEFORE you installed the cat stuff?

[dwtalso]

Nothing voids a warranty ever, ever, ever. It's illegal.

If you swap mid-pipes and the dealer denies coverage for anything but the cats, find another dealer. I've had several O2 sensors replaced with Bassani x-pipes on both my cars and the dealer doesn't care as long as it's clear that the sensors weren't damaged during the intallation. Heck, they damaged a sensor in one case.

As far as the SES light is concerned, there are two levels of diagnostic trouble code (DTC). One type is a mild problem usually caused because a sensor was out of compliance during two consecutive full driving cycles. These lights can come and go over time. The second type is a component failure or serious issue (engine overrun, cat failure, etc) and they never clear.

The best thing to do is get the code read. Checker Auto and Autozone and most mechanics will read the code for you for free. With the code you know exactly what's the PCM is trying to tell you.

So, in the heat, some sensor tripped for two driving cycles then remained clear for two cycles, so the light reset. Next time, if there is one, get it read :).

[norcal_cobra]

An ODB II code reader is a great investment. I got one at Kragen for about $150. You can get units as low as $75. It enables you to read the code, the port is just to the right of your right knee when sitting in the driver's seat. You can also clear the code and turn off the SES light once you've resolved the problem. I had the SES light come on because of a slight exhaust leak.

Here's a good url that looks up and translates the code for you once you have retrieved it from the car. http://www.iequus.com/3100.asp?CatShort=CodeDef

-norcal_cobra

[Hicompression]

Originally posted by Waltman
My tech service guy told me that any messing around with the cat system (replacing with after market stuff) will void your warranty. Did the light come up BEFORE you installed the cat stuff?

As far as what your tech service guy told you....I call B.S. The light has never come on prior to this time and the exhaust has been on for over 4 months.

Thanks to dwtalso and norcal_cobra for your advice.

[dwtalso]

Oh, along the lines of norcal's comments. I have an Autotap. It's more expensive but does data logging as well as manage and read SES symptoms. This is handy when tuning because I can log timing and fuel trim curves. It's a nice tool.