Catalyst

Reply Subscribe

Thread Tools

Search this Thread

Apr 23, 2006 | 01:08 PM

iProDrive

Thread Starter

AudiWorld Super User

Joined: Apr 2006

Posts: 4,186

Likes: 2

From: SL,UT

Catalyst

16815 - Warm Up Catalyst: Bank 2: Efficiency Below Threshold P0431 - 35-00 -

16805 - Warm Up Catalyst: Bank 1: Efficiency Below Threshold P0421 - 35-00 -

Any suggestions on what I should do to fix this? I keep pulling these codes and no one in the Vag-Com forums knows whats going on...

Thanks.

Apr 23, 2006 | 03:54 PM

Max_A6

Junior Member

Joined: Dec 2002

Posts: 1,394

Likes: 0

need new cats

Apr 23, 2006 | 05:56 PM

yrk2.7t@curbside

AudiWorld Super User

Joined: Mar 2002

Posts: 4,460

Likes: 0

Could be O2 sensors as well. Did you mod the car or do any work lately?

Apr 24, 2006 | 09:00 AM

iProDrive

Thread Starter

AudiWorld Super User

Joined: Apr 2006

Posts: 4,186

Likes: 2

From: SL,UT

I had the O2's already replaced....Only thing I have done is the tranny recode...

Apr 24, 2006 | 09:06 AM

iProDrive

Thread Starter

AudiWorld Super User

Joined: Apr 2006

Posts: 4,186

Likes: 2

From: SL,UT

But it was pulling the same codes even before I did the tranny recode....

Apr 24, 2006 | 04:29 PM

yrk2.7t@curbside

AudiWorld Super User

Joined: Mar 2002

Posts: 4,460

Likes: 0

Tranny recode won't affect it, could be o2 sensors swapped left to right or cats are dead.

Apr 25, 2006 | 08:21 AM

iProDrive

Thread Starter

AudiWorld Super User

Joined: Apr 2006

Posts: 4,186

Likes: 2

From: SL,UT

Don't the cats have sensors? Couldn't those be bad?

Trending Topics

UK: Received our first MOT warning on our 2018 A5, now what

21

667
Piston Replacement

20

547
CarPlay & Android Auto Replacement Head Unit?

78

47.1k
Spoiled by 800km

8

183
S5 fan runtime

7

109

Apr 27, 2006 | 02:26 PM

yrk2.7t@curbside

AudiWorld Super User

Joined: Mar 2002

Posts: 4,460

Likes: 0

The O2 sensors are the ones for your cats. Again if they were just replaced they could

have the right and left ones plugged in correctly.

In other words the passesnger side sensor is plugged into the drivers side connector.

So when the engine puleses the exhaust it is off since the sensors are switced.

Just a guess, either the sensors are crossed, or your cats are going.

How many miles do you have?