P0422

[98A4TQ]

From all the old threads on the forum the P0422 indicates a a bad cat converter but I replaced the cat about 10,000 miles ago. Could the cat really be bad after only 10,000 miles. Could the rear O2 sensor be bad and this code goes off. The car is a 98 A4 1.8t. 127,000 miles.

[audinutt]

got a vagcom? only way to know for sure.
could be a bad rear 02. doubt the cat is bad in 10k miles.

-richard

[98A4TQ]

my thread is still here 1 year later. nice. Well I now have 138,000. For the past year the same code P0422 would pop on once a month roughly only when crusing grandma style on the highway and it would shut off after a day or so. Recently its been staying on longer so I replaced both O2 sensors a week ago. cleared the code and it stayed off for a day and is now on and won't shut off. I cleared it but it came back on the next day. So now I have a 20,000 mile old cat and new O2 sensors. I do have a slight exhaust leak I believe, the smell creeps inside when the recirculate is off and Im standing still. But you can't hear any leaking sound. So im thinking Its gotta be a small one. Could the leak cause the light to go on? Other than that the car hits full boost around 7-8psi and runs good even with the light on.
Also how can I use the vagcom to help fix this problem.

[98A4TQ]

also could an aftermarket cat cause this. That is what I installed there. Maybe I should get a OEM?

[audios9]

Its your MAF Sensor, believe me, Do you have a K&N filter? have you been down some dusty roads? Get MAF Sensor Cleaner, clean it off and clear that code and you will be fine.

[98A4TQ]

I havent been down any dusty roads and its a mehle paper filter. I cleaned the MAF last year about 7500 miles ago w/MAF cleaner. But will do it again tomorrow to see what happens. Thanks

[98A4TQ]

So it turns out my cell count on my aftermarket cat is lower than a OEM one. Making it less effecient. Im assuming more like a high flow cat because it was half the size of the stock one therefore trapping less gases. So I did the anti-fouler mod with the auto zone part.And its good to go,no light on now.Hopefully it lasts.

7-19-09 update. Still good to go passed emissions w/flying colors. Anti-fouler works well.

[rovi]

i have the same problem. can you explain to me what the anti fouler mod is thanks.

[98A4TQ]

you can do what many, including myself, did. Go to your nearest Autozone, get the Help! Spark Plug Non-Fouler 42002, drill a 1/2" ID through the non-fouler, and simply use that in between the rear O2 sensor and the cat. Costs like $3. be sure to coat all the threads in anti-seize.

[Seerlah]

Purchase Help! 42002 spark plug non-foulers from Autozone, drill the ID (inner diameter) to 1/2", clean off metal shavings, place on secondary 02 sensor bung, and place the secondary o2 sensor over the non-fouler. Add 2 if necessary.

[rovi]

sorry to bother you. but do you have a picture of the actual thing. i just want to make sure not to screw it up thanks.

[Seerlah]

Look 2 posts up


*I am not rolling eyes at you, just using the icon to have some guy looking upwards

[rovi]

i meant installed. i just don't know where to drill the whole. i already replaced the rear sensor.

[Seerlah]

I really don't feel like taking a pic of mine, bit it is rather strsight forward. If you look at the pic of the non-fouler, there are threads on the outside. Those will thread onto your secondary 02 sensor bung. You will drill the ID of the non-fouler (in the pic) to 1/2" inch using a 1/2" drill bit. On the inside of the non-fouler, there are threads that the 02 sensor can thread onto. The non-fouler will be used as nothing more than a spacer between the secondary 02 sensor and HFC.

The current of the exhaust is too strong and the sensor notices something fishy. So it grants a catalyctic effeciency below threshold code. What you are doing is simply tricking the sensor by decreasing the flow of the exhaust gasses before it hits the sensor.

[rovi]

i see. thanks you so much. ill try to do it today. because i haven't been able to pass inspection. thanks.