2002 ml320, I have check the code with a scaner , o2 sensor, bank 2 sensor 2, I have replaced the o2 sensor with direct fit and reset the code, well the check engine come back with same code I have swiched the o2 with bank 1 sesor 2 still same thing ,, any ideas what is wrong Derek

 

Direct fit would be Bosch #13782 or universal #15738?
I would first check the plug and wiring, or have someone check the exhaust back pressure on cylinder back that you have trouble with. Any rattling from cat. converter or misfiring code?

 

Thank you, ok bank 2 sensor 2 i had to swich the sensor from bank 1 sensor 2 and scan again looks like the new o2 sensor its not working , so i took it back to the store, and have to go to the dealer to get one ( but since i replaced the old sensor in bank 1 sensor 2 , the check engine stays out) but have to clear the code again, thanx again, Derek

 

My engine dummy light came on. I took it into the stealership and they said the computer diagnosis pointed to the 02 sensor. FYI, they charged me $675 to fix, parts and all.

 

Maybe you got very good car wash with it, because the sensor is only around $100 and takes half hour to replace in the slow motion mode! Plus another half hour to plug and unplug diagnostic scanner.

 

how much did the scanner cost? I was in transit from miami beach to houston. Time, quality and cost are variables in my calculation. Is 02 sensor for ML320 same as for ML55?

 

Scanning is free of charge at any auto parts store like autozone. You can also rent one from autozone for $.01 for as long as you need it but you have to make deposit in the amount of the scanner value of $150.
ML55 front oxygen sensors: 000 540 81 17
ML55 rear oxygen sensors: 000 540 28 17
ML320,350,430,500 front: 001 540 60 17
ML320,350,430,500 rear: 001 540 37 17
Bosch 13782 is the OEM sensor - front and rear for ML320 and front for ML55 even do Mercedes part No.s are not the same. Bosch 15202 sensor is used on downstream (rear) in ML55. So it depends on which one of them you are trying to replace.
Bernard

 

Like i said, i was in transit when the engine dummy light came on. I dont have time to mess with it myself, i am not a mechanic. I'll let the dealership service dept look after this problem. And they did while i waited. It was fixed and I continued with my trip.