[bboycircuit]

I just threw this code on the jetta I know what it means, Ive tried fixing the o2 sensor and cat cleaner and nothing worked. Any other ideas or tricks I should try before getting a new cat? If I need one does it have to be OEM or can I do a magnaflow one?

 

[ajsnow6234]

Dude...you should really do some searching for that code... even typing in "Jetta" and "P0420" into Google will get you a TON of answers. Could be a ton of things...do some work first then ask the question.

http://lmgtfy.com/?q=jetta+p0420

 

[bboycircuit]

I did bud, since this is a jetta forum I figured more knowledgeable people would be on here about vw's. Looking for a little advice before I go get a new cat thats all..

 

[ajsnow6234]

Here you go again: http://lmgtfy.com/?q=jetta+p0420

Lots of answers there, a new cat is probably a waste of money.

 

[bboycircuit]

Anyone else on this forum wanna give some advice besides sending me to google ?????

 

[DTR Ruth]

Anyone else on this forum wanna give some advice besides sending me to google ?????

There you go bro: http://search.yahoo.com/search;_ylt...20+jetta+code&SpellState=&fr2=sp-qrw-corr-top

 

[bboycircuit]

ya buddddy

 

[ajsnow6234]

There you go bro: http://search.yahoo.com/search;_ylt...20+jetta+code&SpellState=&fr2=sp-qrw-corr-top

made me laugh out loud...but just a little

 

[jonnyrocket]

had the same issue on my '03 with 168000km. totally random as to when it would come on, but mostly at half a tank into gas that was ethanol blended. mine passed sniffer no problem (it wasnt due but i had it done anyway) i replaced both o2 sensors and it still came on at odd times. not wanting to fork out for a new cat that should be ok if it passed emissions, i contacted vw of canada techs through a freind at their head office. vw has a software update for the ecm that will open the window of sensitivity between the two o2 sensors.

"01 09 10

Apr. 15, 2009 2010348 Supersedes T. B. Group 01, number 09-06 dated Apr. 8, 2009 due to additional

“Note” under Technical Background information.​

Update Programming Engine Control Module to Address DTCs P0300-P0304, P0420 and P0441"
i have a pdf of the tech bulletin straight from vw of canada...man was the dealership unhappy that i wasnt going to pay for a new cat. i did have to pay for an hours worth of labour but it has totally fixed my issue.

​

 

[sandmanH2O]

What year is your jetta?

 

[jonnyrocket]

the tech bulletin and software update also cover the following issues/DTCs

P0300 Random Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0420 Catalyst System Efficiency Below Threshold Bank 1​

P0441 Evaporative Emissions System Incorrect Purge Flow
Guess they were tired of replacing cats under warranty so they wrote a work-around into the ecm, they did my coils under warranty at the same time and im sure if i was under 160,000km they would have given me a cat before admitting to this easy fix. at first they didnt want to do it