Error Code 233 - Catalyst Efficience

[Robert N]

Engine light came on yesterday and INPA gives an error '233 Catalyst Efficience Main cat Bank 1'
There is only one incidence of the error.

Any thoughts?

 

[137699]

Either your cat is reaching end of life or perhaps the O2 sensor is faulty and giving the wrong readings?

 

[Robert N]

Either your cat is reaching end of life or perhaps the O2 sensor is faulty and giving the wrong readings?

Thanks 137699, pretty much what I was thinking, hope it's the latter rather than the former.

Going to use INPA again today with the engine running and watch the Lambda Probe read outs, did it with a cold non-running engine and the readings for the probes are all the same (0.42) when I took a snap shot with the engine running a couple of weeks ago I noticed that there was a ~10% difference in the readouts for the post cat probes and ~400% for the pre cat probes so that MAY indicate a probe problem.