fault codes P0420/P0430
 

Hello,
Quick question probably already answered before....
I've been getting fault codes P0420/P0430 (cat. conv. eff. bank 1 and 2).
Any ideas?
Thanks for your help.

Welcome,
I had the same code P0430. I cleaned my mass air flow sensor with cleaner and cleared the code. Code did not come back. Won't work every time, but that is where I would start. Our sponsor has a how-to on cleaning the sensor. It is very easy to do. Good luck.

TB

I kept getting those codes for about 6 months along with P1128/P1130 and a few others as well. At first, I replaced the 2 Pre Cat O2 sensors, then the Post Cat O2 sensor and then clean the MAF. I cleared between each fix and continued to drive it around. Still kept getting the codes, I finally replaced MAF sensor. I still kept getting the same codes after $500 in parts.
I gave up and ended up taking it to an indie and he said replace the AOS (Porsche). That along with cleaning the intake has fixed it so far, about 700 miles since I've had the codes. Cross my fingers.

If I were to do it over, I would start with cleaning the MAF first, then clean out the intake of oil. Those are quick and easy fixes that are inexpensive. If you are still getting the codes, the next thing I would do is check the AOS for proper operation. Replace it if it is throwing out white smoke at start up.
Good Luck.

If you really want to find out what is going on, scan the car with a Porsche specific scan tool and look at the voltages on the O2 sensors before after the three way cat., paying close attention to what the voltages do. If they are following each other, your cats are on their way out. Both of these codes indicate weak or failing cats.