Catalytic Converter Bank 1 below efficiency???

**subdude** · 10-25-2008 06:34 AM

I have been popping this code lately. Intermittently for about the last two months. I had attributed this two one of two possible causes, either the catalytic converter is bad or an oxygen sensor. I searched this board yesterday and there was a thread in the B5 tech forum that talked about this specific code. There was a lot of discussion about it but no real way to discern which was the fault. I had the idea yesterday that I would proceed as follows since I have less than 80K on my car and I called the dealer to get their take on it as well. I figured since O2 sensors are not covered I would replace the "Bank 1 sensor" and see if the code was generated again the logic being that it should be the cat at that point. The dealer tech I spoke with said he felt that was a waste of time and that it was most likely the cat which required replacement. In order to get that replaced they need to have the code pop twice. The first visit you get charged for the second is under warranty(fair enough). Seems to me there ought to be a better way to determine what the problem is. My take on it is that due to the intermittent nature of the problem I am more inclined to think it is a sensor issue especially since there is nothing physically wrong with how the car runs right now and catalytic converters are designed for the life of the car. Any thoughts???

JR

**tonelee1316** · 10-25-2008 12:32 PM

is it for the first sensor (S1) or second sensor (S2)

**Mike02A4** · 10-25-2008 02:26 PM

You getting P0420 code?

I got that and took it to the dealer, picked the car up the next day with a brand new cat converter 100% free of charge. They did not erase it and make me wait for it to come back. 8 years/80k miles is the federal emissions warranty.

**msharifi** · 10-25-2008 05:01 PM

Originally Posted by Mike02A4

You getting P0420 code?

I got that and took it to the dealer, picked the car up the next day with a brand new cat converter 100% free of charge. They did not erase it and make me wait for it to come back. 8 years/80k miles is the federal emissions warranty.

What year is your car? how many miles?

**Mike02A4** · 10-25-2008 05:52 PM

02 and had almost 79k when I brought it in.

**msharifi** · 10-25-2008 06:37 PM

Originally Posted by Mike02A4

02 and had almost 79k when I brought it in.

Dealer changed it for free because its a emissions part?

**subdude** · 10-25-2008 07:14 PM

I will plug my reader in tomorrow AM to check which sensor and code #(if listed?). Yeah this dealer wants to see the code twice.... Whatever. At the rate it comes in hopefully I won't make it out of their parking lot.

**Mike02A4** · 10-25-2008 08:03 PM

Originally Posted by msharifi

Dealer changed it for free because its a emissions part?

Yeah covered under the federal emissions warranty, 8 years/80k miles. I just made it

**diagnosticator** · 11-02-2008 02:11 AM

Well, look at it this way. If the code pops up twice for the dealer, let them replace the cat for free. Then if it turns out to be the O2 sensor after all, you get to buy a new O2 like you figured originally.