Error code "Inefficient Cat Bank 1 &2" on R230

[cardiffrob]

This code has popped up a few times and been quickly reset. Any ideas as to the cause? The only other fault likely to have been there at the same time was a temp gauge failure. It only clicks the management light on after about 5 miles and at low speed.

 

[lynall]

Have a look on here http://www.mbclub.co.uk/forums/engine/71360-error-codes-p200b-p207e.html poss cat dying?



Lynall

 

[cardiffrob]

Hmmmmm. Thanks for that. The unusual thing in both threads is that both banks come on at once without there being a balance pipe at the start of the system to allow crossover.

 

[w124coupe]

Agreed - a symptom or consequence and not the cause...how did you read the code(s) and what was it/were they?

 

[cardiffrob]

The local garage invested £8000 in a code reader. They reset the message but showed me first that it said "Inefficient Catalyst bank 1" and bank 2. I didn't display a code number, just the description.
They also noted the disparity between the displayed temp and the temp on the code reader (instantaneous) since we discussed the possible causes. I had leaned towards the possibility of the temp gauge being OK and the fault being with the sensor, thus causing the fueling to run rich due to the computer thinking that the engine was still cold. I guess I was off the mark in my assessment!