A poster in the 996TT forum suggested I ask my question here, to the Cayman community.

My upgraded 996 TT (Giac tuning, Kreissieg exhaust, among other things) has developed a CEL issue. The O2 sensors are throwing errors P0172 and P0175 (O2 sensor out of range). I had the guys at Vision Motorsports in Laguna Hills look at it and their conclusion is that one of the cats is failing.
I bought the car with the current exhaust system installed. It is a Kreissieg F1 exhaust with a switch, allowing you to switch from Cats to straight pipes and back again at the push of a button.

The car has less than 40K miles and I am the second owner since May 2009. Since I've had it, the car has been garaged for 3 months out of 5, due to my traveling.

Is it possible that this could be caused simply by a sticky valve on either side? If so, how do I fix it?

I have looked online but there is not a lot of information on these exhaust systems. I have emailed Vivid, who seems to be a reseller. I've also asked Sharkwerks for their input, as the previous owner told me he bought the exhaust from them.
If anyone else has any feedback or any ideas on where to source a replacement cat (and how much that might cost), that would be helpful.

 

Do you get any type of noise, rattle? The cats failed on my 02 996 with only 30,000 miles. When they started to go I could hear a rattle in the right bank. Not very loud but it was there. The cats are made with metal monoliths. When they start to fail the loss of material will make them loose in the housing.

It could also be an O2 sensor issue.

 

don't worry about it. it's normal.
what you can do is turn it off, and maybe it will be came back on a couple of months, then just turn it off again.

on the other hand, you can reflesh your ecu.

 

Thank you for your feedback. There is no rattle or noise of any other kind.

 

This problem seems apply to US models only. Every single time I installed either Kreissieg or Capristo exhaust to my car would cause the check engine light on. But Ive never had this problem on my cars in China.

 

hey pvanosta, we actually have never sold any Kreissegg systems. In fact one of our customers had it on his car and changed it with a system that we do sell and he sold it to Ken I believe (who you bought it from?). A quick search on Google shows that www.gthaus.com is the US distributor for those systems. I would give them a call and go from there.

 

Thanks Alex. That's very useful.