NewBeetle.org Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
Hello, I have a 2000 new beetle, with a 2.0L gas, no turbo, engine. The check engine light has been on for a while so my buddy with a VCDS read a P0422 code, (Main catalyst bank1, efficiency below threshold). I have replaced the catalytic converter about 5yrs ago and had hoped I could fix this with a new O2 sensor, the one closest to the muffler,...It didn't work...the check engine light is still on. Does this look like I need a new catalytic converter?

By the way, The new O2 sensor has a slightly different connector than the origional one. The new O2 sensor came with a replacement shell for the the connector on the vehicle side. In order to use it I have to remove the pins from the vehicle side connector...I tried and tried but could not remove the pins. There is a retaining clip that slides out of the connector but even with this removed the pins wouldn't budge. There seems to be no way to remove the pins from the vehicle side connector. I managed to cram the 2 slightly incompatable connectors together but its a kludge! Has anyone seen this before? Thank you!
 

·
Registered
Joined
·
2,505 Posts
connector problem

Is that a typo, P0422? did you mean P0420?

NO, not the connector issue I have never seen but i used to get the P0420 code before. Glad I didn't replaced the CATALYTIC converter to only find out later that was not the problem. Look at your emissions systems and make sure all those are functioning properly. If you haven't done a tune-up lately than it's time for that. There are a number of things that can trigger that code and I wouldn't change out the CAT first since it's the most expensive part to replace. MY P0420 code has not reared it's ungly head in 3 months now. The only thing I did different is do a complete tune-up, clean the throttle body valve then recalibrate it, switch to Higher octane fuel(93), make sure the engine is running at or over 200 degrees fahrenheit all the time. Clear the codes from the ECU and hope for the best.....LOL :D Good luck to ya..
 

·
5/23/10 <3
Joined
·
11,172 Posts
P0422 is a legit code. Tends to be an 02 sensor more often than a cat. You do have 2 sensors so the other could be the problem. I would see if you can find someone with vag-com and take a peek at the sensor data. Thats how I figured out which one of mine had failed.

Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
9 Posts
Discussion Starter #4
P0422 Code

Thank you for the replies, I appreciate your help. As I recall the code interpretation from the VAGCOM wasn't very specific. I wrote it all down and it just said:

"16806 - Main Catalyst Bank 1 P0422 - Efficiency below threshold"

It sounds pretty vague to me...I have had a lot of trouble in the past with MAF sensors. I'm on my 3rd one. I wonder if that has anything to do with this? Thanks again
 

·
5/23/10 <3
Joined
·
11,172 Posts
Here is more info on the code: 16806/P0422/001058 - Ross-Tech Wiki

If you have the full version of VAG-COM, you can look at the measuring blocks for the O2 sensors and see if they are working properly.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
swapped both O2 sensors still get the check engine light

Hello,
I bought a new rear O2, swapped it out and still got the check engine code. Yesterday I replaced the rear O2 with the one I removed and put the new O2 sensor in the front position. I'm still getting the check engine light. To me this sounds more and more like a bad catalytic converter! Do you agree? I hate to dish out $500+ and still get the check engine light blues but I don't know what else to do....:(
 

·
Registered
Joined
·
9 Posts
Discussion Starter #7
Hello, and thanks for the link. They listed a possible cause for the P0422 code as: "Check Oxygen Sensor(s) Control" I am not sure how to go about that...I bought a new O2 sensor and replaced the one after the cat and still got a check engine light. Then I put the origional O2 back and put the new O2 sensor in the front position. I still get the check engine light. I'm ready to buy a new catalytic converter but I wonder if it will solve the problem...Perhaps there is a problem with the O2 sensor control, whatever that is. Thank you for your time!
 

·
Registered
Joined
·
2,231 Posts
The front and rear O2 sensors are different part numbers and don't interchange. The front sensor is used by the ECM to set the fuel mixture by looking for a particular Oxygen content in the exhaust. The catalytic converter then burns the remaining hydrocarbons in the exhaust and thereby uses up the rest of the oxygen in the exhaust. The second O2 sensor then check to see that the Oxygen is gone. If it detects an Oxygen content too close to what the front sensor detects, then it sets the efficiency code (either P0420 or P0422, in VW's case).

I just replaced my catalytic converter recently. In my case I had the original converter and it had the "can of marbles" rattle for over a year. One day the rattle went away and the CEL came on with P0422. I replaced the front O2 sensor at the same time since it was 14 years old and easy to do with the converter out of the way. The rear sensor almost never fail (unless contaminated or something) because they lead a relatively easy life in the Oxygen-free part of the exhaust.

5 years might be about the expected life for an aftermarket catalytic converter. You can tell from the price how much of the "good stuff" (rare earth metals) is in the converter. Are you thinking of replacing the catalytic converter yourself? I'm going to write up a DIY based on my experience replacing mine.
 

·
Registered
Joined
·
3,690 Posts
Slow down here a bit.

All the catalytic converter efficiency codes are a problem for the industry.

P0420/P0422 are pretty similiar.

So before you do anything else you need to stop and think.

1st, I would not replace the catalytic converter yet.

2nd, I am not sure the O2 sensors pre and post catalytic converter are the same. So you just go swapping them around on most cars.

A few questions.

1. Does your car consume oil? If so, how much, how many miles per quart?

2. Have you verified your engine coolant temperature? You need an OBDII scan tool that will display Real Time data. The engine should be running about 205F after about 10 minutes.

You may have other problems that have triggered the catalyst code.

What is the Long Term Fuel Trim at warm idle?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #10
Update: 2000new beetle P0422 code and O2 connector question

Hello All and thank you for the replies,
After going back and forth I bought a new catalytic converter. I began to remove the old one and got 3 of the 6 flange bolts off no problem. Upon attempting to remove the other 3 I managed to snap one of the studs that thread into the exhaust manifold. I got so disgusted I cobbled everything back together and I am planning to take it to a mechanic. :mad: I'll let you know what happens next. Thanks again for the replies!
 

·
Registered
Joined
·
9 Posts
Discussion Starter #11
2000 new beetle P0422 code, 2.0L gas/no turbo

Well The catalytic converter is in and the check engine light is still on!:confused: It could be for a different code but I doubt it. I thought I was going to solve the problem with a new cat but I took a gample and lost! I need to get the codes read again...I wonder if I'll ever get past this!!! I need to get rid of the check engine light so I can get the car inspected. I do use just a little bit of oil by the way...very little. I don't know about the coolant temperature I'll have to check into that. Thanks again for the responses.:( I still need a windshield and new tires to make this car road worthy...I'm starting to have doubts if I'm throwing good money after bad. What's next, the dreaded timing belt???
 

·
5/23/10 <3
Joined
·
11,172 Posts

·
Registered
Joined
·
2,231 Posts
Did you reset the check engine light after you replaced the cat? The P0422 shouldn't come on right away after the reset even with a bad cat. It takes a few miles of driving.

So, have you replaced both O2 sensors at this point? What were the sensor types (brand & part #) that you replaced them with? Also, is your new cat one piece with the downpipes, or was it a weld-in type?
 
1 - 13 of 13 Posts
Top