P0421 code

[Major-eyeswater]

Hi all.
This code popped up this morning, no change in driveability though.
Wondering if anyone knew the cause before I have to trawl through google...

Cheers.

 

[KiwiDan]

Google told me..."The P0421 code means that the powertrain control module is noticing that the catalyst system is not performing as it should during warm up conditions. ... The powertrain control module uses data received from the upstream and downstream oxygen sensors and compares the two readings given."

 

[S-Star]

did you sort out this Fault code..? as ive got the same.

 

[Major-eyeswater]

No.
I've had the code twice in the last 3 weeks and each time I've cleared it - not too sure what it is though.

 

[S-Star]

ditto.. i think ive checked everything. (i think) . mine pops up every 50/60 miles or so.. never when driving.. only pops up when im slowing right down or stopping at traffic lights on just tick over.. Audi dealers wanted over £200 to have a look at the for 2 hour...