Aftermarket exhaust = dreaded CEL? Help!

After cruising the board for over a year, I finally made the time to join. I have an 01 C2 tip with 32k on the clock (CPO expires 10/06). Unfortunately, the CEL came on monday am. Mods added back in June were the Fabspeed Headers & Exhaust kit. Here's the dilemma: After 4 days waiting for P service manager to call me back (my LA dealership sucks), I have to physically show up at the dealership today to get the 411 (PCNA survey people will hear about this . . . time is not money, money is time). Apparently, the aftermarket exhaust/headers are throwing 'out of range codes' on the lambda/02 sensors, ergo the CEL. Spoke with both the service manager and the tech. They reset it gratis, smiled, apologized and advised that I should put the stock stuff back on. Some questions from a neophyte like me: A. Is this a reasonable explanation? I haven't heard anything about aftermarket pipes and CEL before . . . B. Why 4 months later? I've driven the car pretty hard in the interim and was coasting downhill . . . C. If I keep the mods, the CEL could come on in 2 minutes, 2 days or 2 years from now, so they advised (wink, wink) if so, to not worry about it unless the CEL flashes. Great, so what happens when something really does go wrong with the car? How am I supposed to know? D. If I go back to stock (have to chase down the parts from the tuner, ugh), back to sewing machine sound and at least a psychological drop of 12hp. The Fabspeed combo does sound great � how the car should sound IMO. So what about taking an additional $2300 hit on the PSE for warranty security? E. Could I unplug the battery to reset the DME so it can remap? Buy an OBDII reader? F. Last but not least I'm feeling like a Texan in Tikrit about $$$ repairs not covered by warranty given some of the horror stories I�ve read about. I already got a new tip tranny installed under warranty a few months ago and believe the work would have been around $8k. Anyways, I have a ton more questions, but won�t bore you with my petty problems. Really, in the whole scheme of things, owning a P car we should be pretty thankful. As for the car, love it, love it, love it! Just had to postpone my 997S purchase for a new babymobile . . . reminds me of a saying �What if man�s grasp shall exceed his reach? Ah, but what �tis heaven for.� Enjoy the pix & thanks for the help.

I'm not familar with that exhuast system and without knowing the fault codes your dealer found in your DME its hard to say for sure, but if your new exhuast has high flow cats in, its possible your CEL could be from a catalyst efficiency code. Oxygen sensing out of range faults are usually caused by MAF sensor problems, vacuum leaks, or other problems.

I had B&B headers & mufflers for 6 years on my C2 and they never once tripped the CEL. Before you scrap what you have, go to a good independent and have them diagnose it (probably your MAF given the mileage...mine crapped out with about that many miles and I had the same symptoms you're having). Clearly, the dealer is too "busy" to fix your problem. Buy your next one somewhere else.

Holger is likely right. A MAF failure will give you 02 codes. The other possiblity is a bad O2. Is your car down on power? Your exhaust system will not cause the problem. My exhaust system is 8 inches long. I consists of a pipe running straight from the header out the opening in the bumper. The pre-cat O2 sensor is in the pipe. The post-cat sensor is hanging outside the system in clean air. If my system doesn't cause a CEL then your's certainly shouldn't. Jim

Thanks guys for the help, will go get an independent shop to check it out and get the DME fault codes - chasing the problem from there. btw, I already had the MAF sensor replaced about 6 months ago . . . Many thanks!

If the MAF was replaced before I guess its the MAF. BTW what dealer were you dealing with in LA?

Rusnak in Pasadena, very nice guys, but you really have to stay on top of them to get answers. When my tiptronic went a few months ago (it was really kicking hard when downshifting from 5th to 3rd, with a WHACK!) it took them 2 weeks to diagnose and drop a new one in. Of course, it was under warranty, so in the end I shouldn't complain. However, they would only spring for a 1 day loaner car which is just irritating. Anytime my old BMW or Merc is in for service, they give you something comparable for however long your car is out. btw, any recommendations on independent shops in the LA area? My current strategy is continue to drive it until the CEL pops up again and take it over to the independent for a full DME readout (which the dealer didn't give me, ugh) and then take the car back over to the dealer and see what they come up with. If I get the same song & dance, that's when I'll pull out the independent shop's DME codes . . . sad we have to be so strategic in life sometimes.

Hegermon, I usually do most of my own work on mt cars. I have many friends who are mechanics that has the diagnosis tools when a CEL pops up and I work from there. I have used Star Service in West Los Angeles for some work on my old 951 and they work on various Mercedes that I own. They are good guys who usually finds thoes nagging electrical problems. I also recomend Callas Rennsport in Torrance.

Thanks jetskied, will check them out.