kgrig

The check engine light came on today, and the performance of the car has not changed at all. Got this code pulled up from auto zone.
They told me probable causes are:
1. Failed Catalytic Converter
2. Engine misfire or running condition
3. Large Vacuum leak
4. Engine oil leakage into exhaust vale guide seals.

Wont I notice if any of the above are happening except #1. What are the chances of the converter going bad?

Is there any track record with these codes on the A4s?

Thanks

JAFO

could be the post cat O2 sensor.

kgrig

is there a way to check to make sure it is it...don't want to order one without knowing for sure...

JAFO

if you know anyone with a vag/com they could check the output.

kgrig

the vagcomwill give more info than a standard obdII tool?

JAFO

it can read the output voltage of the O2 sensor. i'm not sure an obd2 can do that.

Audi_kraut

Note that a bad CAT will effect the output voltages, so it doesn't always mean that it is the sensor