P1117, P1121, Po131, Po151, Po137, Po157

[paulv]

Originally Posted by root_werks

Paulv,

It's just a guess on my part, but after replacing all 4 O2's now and all the other CEL's gone with only the P0430 present. I can now test and pass all 4 O2's so I am hoping it's just a bad Cat. I would assume so since the PO ran with faulty O2's for almost 3 years! I'm sure the Right Cat is clogged (ruined) and the left isn't far behind.

I found a pair of good low mile cats for $350 shipped to me. The 4 O2's, MAF, 2 front tires and lots of other little maint items have left my Porsche fund a little dry. Gotta water the money tree for a bit. Meanwhile, I'm trying not to drive the car much.

Upates to come....when I get some more money.

That code is for Bank 2 which is the driver's side (Bank 1 has the #1 cylinder in it and would have the P0420 code). If you have a buddy who owns or has access to an exhaust gas analyzer, you could measure all the gases (NOx, CO, HC, O2, CO2) before and after the Cat to prove it bad (or good). BTW, running with bad O2 sensors will make the car perform lousy as well as destroy the cats. Attached a little tutorial about exhaust gases.

Regards,
paul...

[root_werks]

This was a recent purchase for me (not my first Box though). It runs great and had no real notable change when the O2's were replaced other than the CEL's didn't come back. So there might have been a short in one of them? I didn't bother to test them after replacement.

420, right, sorry I was thinking engine orientation backwards, I should know that. I don't know anyone anymore that does the analyzing, but I'm sure I could track down a local shop that'd do it for a couple of bucks. Probably worth it. Why replace a cat when I may not need to?

Other thing I was going to try this weekend was swap O2's from side to side. See if I get a P0420 instead of a P0430. If I do, then I know one of my new O2's is probably bad.

So, still things to check. Good side is codes are different and there's only one now.

[paulv]

Originally Posted by root_werks

...............................................

Other thing I was going to try this weekend was swap O2's from side to side. See if I get a P0420 instead of a P0430. If I do, then I know one of my new O2's is probably bad.

...........

You didn't mention it but I'm assuming that you will be swapping the "after cat" O2 sensors from side to side, as these are the ones whose signal is compared to the "pre-cat" sensor to determine cat efficiency (a required readiness monitor under OBD2 mandates) and sets the P0420/30 code when the efficiency falls below a predetermined limit.

Regards,
paul...