bldn10

987.2 w/ TPC turbo, Cobb w/ TPC tune
The cats in my stock headers were badly deteriorated so I replaced them w/ Fabspeed Race (catless) headers. Also replaced Bank 2 upstream O2 sensor. Made a big difference. What DTCs can I expect solely because of not having cats? 2414 is permanent and is Bank 1 upstream O2 sensor sample error. I have a new one ordered. But I'm also getting 0171 and 0174 which are Fuel Trim System Lean. Is that due to no cats or something totally independent? Any others I shouldn't worry about?

badabing

I had Fabspeed catless headers and utilized their minicat O2 spacers.

I also had them send me a Cobb tune file.

I kept getting codes P0136 and P0156. Struggled with this for 2 years.

In the end the solution was to remove the minicats which I didn't really need because the tune file coded out cat efficiency codes.

bldn10

I got the new O2 sensor in and started to remove the old one. As soon as I touched it w/ the wrench it moved. It was loose, not even hand tight. Mechanic error. Tightened it and now I'm only getting 2414 and I think I can live w/ that.

The_Texan

I'm dealing with these same codes. Just ordered a softronics tune, and the code came back on after 45 miles.

Softronic

Hello,
If you have minicats remove them as they will cause faults or if you just have catless headers make sure the O2 sensors are in the correct positions. Many catless headers will put the first primary O2 sensor in or at a single pipe and it needs to be after the collector to properly sample the entire bank and not just one cylinder. The secondary or post cat O2 sensor can then go in the single or more prone to the single cylinder. Many headers on the 987.2 and 997.2 are like this.

You can also get other faults from the incorrect angle or depth from aftermarket headers as the positioning for sampling is also crucial and more so for the newer cars with the sensors. Having loose or damaged ones.

The only faults that you should get for failing , failed or eliminated cats are for the Cat Efficiency and these can be P0420, P0430, P0421 or P0431.

While other codes can be removed with tuning its better depending on the faults to correct them rather than just delete them.

Best,
Scott