O2 upstream sensor 2008 W204- C320cdi

[Merc59]

Decided yesterday to make a run to Toolstation, for some DIY materials, which was non eventful until I got into the car to come home only to see a dreaded EML light! The car drove fine with no issues of power or gears got home but unfortunately my cheap code reader wouldn't read the codes! have friend coming tonight with a more expensive code reader which showed a fault on the upstream O2 sensor.
anyone know how many are on this car? As it didn't say right or left bank I assume it's just the one?
Can someone please confirm if it's the case and a part number also.

 

[ChrisEdu]

Probably 2 per- exhaust pipe - one pre and one post-cat.

 

[OneForTheRoad]

Just one on the diesels . Even a V6 and straight 6 has only one. This maybe yours . It's a 5 wire type. Located behind the front wheels area. Wire length is also important.

 

[BlackC55]

It may not be that thats causing the light btw. I would try a even better code reader. Some code readers dont pull all the codes.

 

[Merc59]

Just one on the diesels . Even a V6 and straight 6 has only one. This maybe yours . It's a 5 wire type. Located behind the front wheels area. Wire length is also important. View attachment 139405

Thanks for this will check on website

 

[Merc59]

It may not be that thats causing the light btw. I would try a even better code reader. Some code readers dont pull all the codes.

He's a mechanic and used a snap on solus plus unit looked at one and at a cost of £650 I think I'll pass on it

 

[BlackC55]

Even the Snap On kit doesn't pull all the codes all the time.

 

[Supernoodle]

If the MIL is on, you've got to be able to read the code that is requesting that with a basic OBD2/EOBD tool.