Code Analysis

[DerekF]

I've had a few CEL activations since I bought my 2009 C2 PDK, which haven't resurrected since I swapped the gas cap. I have however, a set of error codes left that I'm trying to resolve on Bank 2

 

I've got:

P2198  Oxygen sensor ahead of catalyst convertor BANK 2 - too rich signal

 

and

 

P2A04  Mixture behind catalyst convertor. BANK 2. Implausible.

 

My gut reaction was 'Change the sensors', but thinking about it I'm wondering if something else is underlying. As the sensors are returning a signal, I'm wondering if it is something upstream that is causing the issue?

 

Has anyone seen these codes together and have you any suggestions? Many thanks

 

D

 

[Loren]

 

P2198 Lambda correction downstream, bank 1 – rich/lean control limit exceeded

 

Possible fault causes:
- Leakage in exhaust system between the two oxygen sensors
- Oxygen sensor upstream faulty (contaminated/aged)

 

The most common fault cause is a leakage between the two oxygen sensors, resulting in the sensor downstream measuring more residual oxygen in the exhaust than the sensor upstream.