[jayno20]

This is on a 2005 beetle, I am reading that it might be covered under a warranty by volkswagen. Is there any truth to this?

 

[red99]

The code is for low efficiency on the catalytic converter:

P0420 VOLKSWAGEN Catalyst System Efficiency Below Threshold Bank 1 OBDII Engine Light Trouble Code | Engine-Codes.com

If your car is still under the emissions warranty it should be covered assuming that is actually the problem. You could call a dealer and find out.

 

[esse10]

p0420

The infamous P0420 code rear's it's ugly head again...LOL Good luck chasing that ghost fella.....and let us know what you find.

 

[jayno20]

The infamous P0420 code rear's it's ugly head again...LOL Good luck chasing that ghost fella.....and let us know what you find.

Oh lord... will a dealer be able to tell which one of the 10 possibilities is causing the check engine light? lol.

 

[red99]

If your car is still under emissions warranty you will definitely want them to look at it because one possibility is that it is that the catalytic converter has gone bad. In that case it would certainly be worth your while to get a new one installed for free. If it not the converter they will tell you what is wrong. All this assumes you are still under emissions warranty so you need to figure that out first.

 

[Smileybug]

I think standard emissions warranty is 8 years/80k. So it depends on your mileage and when your car went into service, as this would be 8 years.

 

[jfoj]

My 1.8t had the P0420 code early in its life. At the time the dealer replaced the catalytic converter, which was likely dropped at some point before it was installed as it has a large gumball piece of the monolith break off and get caught between the 2 converter sections and sounded like the car had marbles in the exhaust.

I believe at some later date there may have been a ECU upgrade that addressed cold start stalling as well as the "phantom" P0420 codes.

Many of the cars that have P0420 codes may have had exhaust leaks, cracked welds on O2 sensor bungs, questionable O2 sensors and could have questionable catalytic converters, but what I have found is rarely is the catalytic converter the cause.

If you might be still covered under warranty and/or I think the 2.0L cars may have had extended coverage for the catalytic converters or an emission recall campaign?? Then you could speak with the dealer, but they will see you everything they can. You can purchase a decent aftermarket catalytic converter/downpipe/flex joint assembly for around $250, so keep this in mind before you deal with the stealership and get your wallet cleaned out.

If you do not go the dealer route, suggest you clear the code and see how long it take to come back.

Likely the code will not come back for a fair amount of time. Usually they only trigger when driving on the highway and usually on long downhill grades where you are on the throttle very lightly and/or coasting.

Many other makes and models had similar problems and the solution for many manufacturers is to slightly widen the window for the P0420 code to be triggered as many times the window was too narrow and the ECU code was too sensitive.

Again, you could possibly have the ECU reflashed at a dealer or good Indy, but this likely will be close to $250 at the dealer?

 

[Smileybug]

Early 2.0's had an extension, as the cats were commonly failing internally on the AEG motors. Mine did. It all just fell apart and I had a nice little rattle. That was definitely the cat.

I would hook the car up to VAG-COM and take a peek at your O2 sensors.

 

[esse10]

P0420

My 1.8t had the P0420 code early in its life. At the time the dealer replaced the catalytic converter, which was likely dropped at some point before it was installed as it has a large gumball piece of the monolith break off and get caught between the 2 converter sections and sounded like the car had marbles in the exhaust.

I believe at some later date there may have been a ECU upgrade that addressed cold start stalling as well as the "phantom" P0420 codes.

Many of the cars that have P0420 codes may have had exhaust leaks, cracked welds on O2 sensor bungs, questionable O2 sensors and could have questionable catalytic converters, but what I have found is rarely is the catalytic converter the cause.

If you might be still covered under warranty and/or I think the 2.0L cars may have had extended coverage for the catalytic converters or an emission recall campaign?? Then you could speak with the dealer, but they will see you everything they can. You can purchase a decent aftermarket catalytic converter/downpipe/flex joint assembly for around $250, so keep this in mind before you deal with the stealership and get your wallet cleaned out.

If you do not go the dealer route, suggest you clear the code and see how long it take to come back.

Likely the code will not come back for a fair amount of time. Usually they only trigger when driving on the highway and usually on long downhill grades where you are on the throttle very lightly and/or coasting.

Many other makes and models had similar problems and the solution for many manufacturers is to slightly widen the window for the P0420 code to be triggered as many times the window was too narrow and the ECU code was too sensitive.

Again, you could possibly have the ECU reflashed at a dealer or good Indy, but this likely will be close to $250 at the dealer?

That's why I hadn't reflashed mine at the Stealership, heck I can drive around with a pesky little light that comes and go's all the time than to pay 250. It would be nice to know if your ECU has been reflashed already to the latest software upgrade, does anybody know if that can be done with the vag-com ? any cyber smart folks out there?

 

[jayno20]

My 1.8t had the P0420 code early in its life. At the time the dealer replaced the catalytic converter, which was likely dropped at some point before it was installed as it has a large gumball piece of the monolith break off and get caught between the 2 converter sections and sounded like the car had marbles in the exhaust.

I believe at some later date there may have been a ECU upgrade that addressed cold start stalling as well as the "phantom" P0420 codes.

Many of the cars that have P0420 codes may have had exhaust leaks, cracked welds on O2 sensor bungs, questionable O2 sensors and could have questionable catalytic converters, but what I have found is rarely is the catalytic converter the cause.

If you might be still covered under warranty and/or I think the 2.0L cars may have had extended coverage for the catalytic converters or an emission recall campaign?? Then you could speak with the dealer, but they will see you everything they can. You can purchase a decent aftermarket catalytic converter/downpipe/flex joint assembly for around $250, so keep this in mind before you deal with the stealership and get your wallet cleaned out.

If you do not go the dealer route, suggest you clear the code and see how long it take to come back.

Likely the code will not come back for a fair amount of time. Usually they only trigger when driving on the highway and usually on long downhill grades where you are on the throttle very lightly and/or coasting.

Many other makes and models had similar problems and the solution for many manufacturers is to slightly widen the window for the P0420 code to be triggered as many times the window was too narrow and the ECU code was too sensitive.

Again, you could possibly have the ECU reflashed at a dealer or good Indy, but this likely will be close to $250 at the dealer?

It is a 2005 with around 93k miles on it. How would I go about finding out if the cat is still covered under the emission recall campaign?

I cleared the code a few times and it does take a few days to come back, problem is I noticed a significant drop in gas mileage since this light has been coming on as well so I wanna get it fixed for that reason.

 

[red99]

How would I go about finding out if the cat is still covered under the emission recall campaign?

Call a dealer and give them the VIN.

 

[jfoj]

It is a 2005 with around 93k miles on it. How would I go about finding out if the cat is still covered under the emission recall campaign?

I cleared the code a few times and it does take a few days to come back, problem is I noticed a significant drop in gas mileage since this light has been coming on as well so I wanna get it fixed for that reason.

Mileage drop would not be caused by the light and the code.

If you think you need a catalytic converter replaced, you can get a decent aftermarket one for around $250. I found one from a seller on ebay that I think was Muffler Express out of Canada. They had the nice mesh flex joint like OE and used stainless pipe. I did not like the Walker or other units that did not have the mesh style flex joints.

Mileage drop could be caused by a catalytic converter plugged up, however, the MOST common cause of mileage dropping is a bad thermostat and an engine that is running cold.

If your scan tool can read real time data, check the engine temp. Should be a solid 205F even on the highway.

See the link below in my signature about thermostats.