Oh no...Error code P0422?

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golden1245

Active Member
Joined
Sep 6, 2011
Messages
211
Car
1999 C230K Sport
Just got a check engine light and BAS/ASR light come on this morning. I took it to a auto parts store to have the codes read and the only thing it threw back was a P0422.

Definition: Catalyst efficiency low-bank 1
-probably causes: Cats defective, engine misfire, large vacuum leak or engine oil leakage into exhaust valve guide seals/piston rings.

Engine is running smoothly, no misfires or loss of power yet...

I'm not sure if there's a vacuum leak...so it should mainly be the O2 sensors or the catalytic convertor right? :dk:

Let me know if you guys can shed any light on this. I'd like to research as much as I can before going to the mechanic. Thank you for reading :)
 
Have you tried clearing the fault codes and seeing if it re-occurs?
 
What kind of diagnostic code reader did they use?
 
sounds like they used an obdII reader - if so this is only a guide - need to get it on STAR - make sure the guy who operates it is competent - do some research - otherwise you could end up with multiple bills for thousands - that statement is based on fact - just look throuh the posts on this forum and other benz related forums.
 
Turns out the code was caused by a vacuum leak instead of faulty cats. There was a finger sized hose that came lose from the engine that was correctly diagnosed by an experienced Mercedes technician. Turns out the OBDII reader wasn't a good enough diagnoses.

The BAS/ESP light was caused by a brake light switch.

Thanks for the help guys! :)
 
sure! It's that cloth covered hose sticking out of one of the hoses of the oil separator.

8421150031_835f46fb67_z.jpg


And it was suppose to be connected to one of the nipples on something near the engine...

8422243070_d5e680d2e3_b.jpg


The old hose was completely deteriorated and not attached to where it was suppose to be. After he reattached a new one to it and reset the light, the code never came back.
 

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