If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)

Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Please note that it is not permitted to have referral links posted in your signature. Keep these links contained in the appropriate forum. Thank you.

https://www.boards.ie/discussion/2055940817/signature-rules

Hi all,
Vanilla are planning an update to the site on April 24th (next Wednesday). It is a major PHP8 update which is expected to boost performance across the site. The site will be down from 7pm and it is expected to take about an hour to complete. We appreciate your patience during the update.
Thanks all.

Audi A4 Fault query

bbability · 2008-04-14 19:31:50

Hi, Can someone tell me which oxygen sensor is that's faulty. I used Vag-com to find the fault and it has also been diagnosed with Bosch Esitronic software. Same fault found on both. 1 Fault Found: 16804 - Catalyst System: Bank 1: Efficiency Below Threshold P0420 - 007 - Short to Ground Is it the sensor on the manifold or…

14-04-2008 8:31pm

#1

bbability

Closed Accounts Posts: 2,504 ✭✭✭

Join Date: February 2005

Posts: 1911

Hi,

Can someone tell me which oxygen sensor is that's faulty. I used Vag-com to find the fault and it has also been diagnosed with Bosch Esitronic software. Same fault found on both.

1 Fault Found:
16804 - Catalyst System: Bank 1: Efficiency Below Threshold
P0420 - 007 - Short to Ground

Is it the sensor on the manifold or the sensor on the other side of the cat??

0

Comments

#2 14-04-2008 11:22pm

Timmaay

Registered Users Posts: 11,394 ✭✭✭✭

Join Date: April 2007

Posts: 11333

It's saying that the Catalyst is at fault, so that would suggest that its the o2 sensor downstream of the cat. Search these forums for that code, those boys know their stuff.

0
#3 15-04-2008 12:54pm

Mr.Diagnostic

Registered Users Posts: 937 ✭✭✭

Join Date: September 2006

Posts: 906

P0420 is set when the cat has failed the cat ageing test. Basically the cat is not as efficient as it should be. A magic "mechanic in a tin" cure could help but it is likely that it needs to be replaced.
P0420 does not point to either lambda sensor being faulty, quite the opposite.

0