2002 allroad

Have P0421 code which is for a bad catalytic converter passenger side. My local independent (reputable with VW/Audi) said there was a fix I could get from the dealer and to try that first.

The measuring tolerance on the allroad are so tight, the ECU throws a code even though the system is operating within acceptable tolerances.

The fix is the dealer reflashes my ecu to relax the tolerances instead of paying for a new cat. I pay for a flash instead of a brand new cat. Cheap by comparison with a cat running nearly $1,500.

Now for the problem....I can't find a dealer who will hunt down the flash or perform the flash. Audi North America (after research) said the fix is no longer available or supported!!! They no longer provide this to the dealers and basically sorry about my luck...

Anyone have an inside track that can help me???? Any help is much appreciated!! I'm in Baltimore, MD.

Peter Badore

There are specialty suppliers that sell spacers to move the O2 sensor after the catalytic converter out of the exhaust stream. This will reduce the number of times the ECU thinks the cat is below efficiency. I used one from Design 42 on a GTI VR6 operated in Mexico with a cat delete pipe for about 5 years and 50,000 miles and had the low efficiency DTC on about 3 or 4 times.

Luxus Panzer

1500 for a cat is dealer item with entire downpips.

Just get a indie exhaust shop to weld in a universal car...cost approx 100 bucks.

jschick

you can also search for the Diode mod, which you basically add a diode to the sensor wireing, which will lower the voltage from the sensor so the computer thinks its ok. this mod takes less then 10 minutes and is my preferred method

2002 allroad

I've had everyone tell me the aftermarket cats just don't hold up compared to the OEM, any experience on that?

Sounds like o2 spacers may be the ticket.......or if someone knows a way I can get someone to widen the tolerances....

Thanks again everyone.....

2002 allroad

Thank-you....I'll look into this too!

2002 allroad

Diode mod didn't work! I now get P0141 for the side I experimented on.

Anyone have experience in getting rid of my dreaded P0421 code without replacing the cats? Thanks!

O2Allroad

If you end up needing to replace the whole thing and want to stick with OEM parts, www.audipartsdepot.com is a good option, $675 for the whole right downpipe / catalytic converter.