Rhabdo

Can someone help me out here and explain exactly what fault code P0432 mean? Code reader read: P0432 Main Catalyst Efficiency Below Threshold Bank 2.

I did some research and some say it's a bad catalytic converter. Some say bad oxygen sensor? Some say dirty MAF sensor so on and so on......... I'm expecting the worst; catalytic converter. The check engine light just came on today. So I went out and bought and code scanned my s500. I appreciate any feedback.

Plutoe

There is much confusion---post the VIN to be correct.

PSou have been confronted with much misinformation!!

Rhabdo

Thanks Plutoe for responding.

VIN# WDBGA51GXVA330961

Plutoe

First for clarification P0432 is a fault in the left cat.Simple as that

However the factory docs state that if at the same time you also had a front 02 sensor fault, then they suggest replacing the front sensor and if the 0432 fault does not return your cat still has some life,but if that was not the case then the cat should be replaced.

I know what you are thinking--try replacing the left front 02 sensor and see what happens----I guess if it were me I would try---your choice!!

FYI With a good cat the voltage amplitude of the rear sensor is 50 percent of the front

Rhabdo

Thanks for the info. Do you know of any good aftermarket cat converter substitution from Mercedes. I'm old school and only do original parts from dealers but this time around I know these cats are real expensive. I'm located in California. Yes, I know what your thinking, it sucks to own any vehicle in this state. So many regulations. Thanks.

Plutoe

Regrettably I do not,however if I did I would be very careful on what is replaced and for that reason I would start visiting muffler shops and get their input. I am sure that after a few interviews you will know who not to consider.

FYI they all have, or should have, crossover books to direct them to the correct cat!!

oldsinner111

there are several california cats on ebay,some high flow too.

pncurtis

If you are anywhere near Northern San Diego County I would be happy to give you the name of someone to speak with over the phone who will know the answers to your questions. I have been a customer of theirs for several years and have never been steered wrong on anything done to my '97 S420