lamda sensors banks

[alicecooper18]

Hi, anyone know what the bank numbers mean ie bank 1 and bank 2, i think its left and right but which is which
sensor 1 is front and sensor 2 is rear of cat but i dont know what the bank means.
Any help much appreciated.

[v6dub]

what car is it on? is it a v6/v5?

[monkeycheese]

It's V6 4motion - father in law wrote this for me...

Fault code is P0420 Catalyst efficiency below threshold (bank 1) - already changed front lambda's and MAF as suggested by vw but MIL light still on! Was going to change back ones in the hope its not cat but any suggestions?


on diagnostic it looks like 2 back ones are giving different readings but i don't know what correct reading should be hence why i wanted to know which bank is which so I could just change the one lambda thats needed rather than both!

Cheers - James

[alicecooper18]

Hi V6dub,
It is a V6, I'm just trying to understand what the diagnostic is telling me.
Cheers

[CB_VW_Basic]

It's V6 4motion - father in law wrote this for me...

Fault code is P0420 Catalyst efficiency below threshold (bank 1) - already changed front lambda's and MAF as suggested by vw but MIL light still on! Was going to change back ones in the hope its not cat but any suggestions?



Cheers - James

Have you recently changed the cat? I had the exact same error message on my car after a new aftermarket cat fitted. I've had that cat replaced now for a larger more appropriate unit and the error message has gone.

[monkeycheese]

thanks for replying but no new cat has been fitted although I think I may need to if changing the rear lambda's doesn't work!