I have a 2003 Audi A4 1.8, bought it 15 months ago, 202K miles. In Mar 2013, had a new (I hope) cat converter, both O2 sensors and a purge solenoid put in at an AAMCO, total = $2400. 10 months later, I just failed the NYS inspection with a P0420. I went back to the AAMCO to get info on what exactly was installed but they're closed - no indication of when or why. Belatedly checked the place on BBB, find they're rated F. Contacted AAMCO Corporate, not holding out much hope there.

I know there are many emission-related possibilities with the P0420, some relatively trivial. Two questions:

- Can a good mechanic tell what the specific issue is?
- Is there any way to know by looking at it whether the cat converter was new, or just a piece of junk?

The Audi dealer and NYS mechanic both say I need a new cat conv, but that may be just their automatic reaction to any P0420.

Paid $3500 for the car, have put another $5500 into it for repairs - forget about gas, tolls, insurance. Close to junking the car, though I really need it to save a massive commute to work.

Thanks!

 

Good luck!

The bozo's at Ammco probably installed a aftermarket catalytic converter. They are a Temporary fix at best. They are usually good for a year or so.

The proper way to fix that code is to install a factory new cat , replace both O/2 sensors.

There is probably a good reason that they are not opened any more , they are not able to properly fix cars.

 

I agree with the A/M catalyst comment. As a tech in an Indy shop (former Audi tech) we now only use aftermarket if an OEM is no longer available OR it exceeds the value of the vehicle (to use OEM) but the owner wants the CEL off (no emission testing here). No sense spending $1,200 plus labor to install a cat on a car worth $1,500 for example. They seem to be hit and miss. Catco brand is usually OK, others not so much.