Trying to wrap my head around fault code P0430 and P0420

[KRAM36]

Originally Posted by Topless

Sounds like something is fouling your cats. Expensive fix if they get fully loaded up. Yr, model, mileage, any recent work done, sooting tailpipe, burning oil?

2003 S 115k miles. No recent work done. Normal sooting on the tailpipe, no oil burning. I'm actually about 2k miles past when I should have changed the oil and the dip stick is still within normal range. I'm changing the oil today.

Originally Posted by san rensho

Do a graph of the pre cat and post cat voltages. If the cats are good, you should gbet an appriximation of a sine wave on the pre cats and close to a straight line on the post cats. If you have a major variation, then the cats are probably bad.

I need to get more familiar with the Durametric, just got it a few days ago. I was reading about this.

Originally Posted by mump

I'd put money on the MAF sensor. This summer I got the P0430 code, took it to the Porsche dealer since it was real close when I lved in Germany. They cleared it and said no big deal unless it comes back. 2 days later, P0420. Cleared it. 2 days later, P0430. It did this 5-6 times. I went back to the dealer requesting my O2 sensors changed. They said I would be wasting money and told me to get a new MAF sensor. Ordered it from Rock Auto since it was cheaper. Never got the code since.

Oh, yes this was another fix I read about. I'll clean it today. I forgot about that one.