casper_c230

Thanks for your response, but I don't see how it's possible to do it from the top. I looked from the top of the engine bay at where the other end (not the end that connects to the cat) leads and it's plugged in underneath the oil filter down about a foot. There's almost zero clearance there. The wire plugs parallel to the length of the car towards the front.

Have you done this yourself or is this hearsay? From reading your past posts on this subject and others, you seen very knowledgeable. I have no reason to doubt your posts, but I can't help but to question you on this one b/c after visually inspecting how the O2 sensor would be removed, I can't possibly fathom that it can be done from the top. Maybe there's something you know that I'm missing. I'd love to be wrong and be able to do it from the top. Mind sharing exactly how you personally did it?

If it requires removing the air box again and removing the oil filter as well, it's definitely easier to do it from the bottom. Even with the two components removed, I still question if there's access to the plug from the top. Please share your know-how. The more details the better. Thanks.

Glyn M Ruck

I have tried to reply to your email but it just bounces back.

Subject: O2 sensors

Hi,
Your O2 sensors should be as per pic attached. Just trace the wire back to where it plugs into the engine wiring harness plug. We have the steering column to contend with on SA cars on this side but we have never had trouble unplugging O2 sensors. Maybe our harness is different but I don’t think so for the engine harness. We are talking about the primary pre Cat sensor - Yes?
Good luck

Regards,

Glyn



ps. If it is difficult on LHD vehicles then take the bottom plate off & go from beneath.

casper_c230

Perhaps our mixup is between the left-hand drive and right-hand drive models. The USA left-hand drive models definitely cannot have the o2 sensor completely removed from the top of the engine bay.

Thanks for the response and the time you took to upload the pic though. You're right about how easy it is to remove the O2 sensor end from the cat end, but removing the other end needs to be done from the bottom. Especially since the tab for the plug needs to be released there's really no way to do it from the top of the engine bay. It's very accessible from the bottom as seen in my attached photo.

I'll post more info on the DIY here for anyone else who needs it.
https://mbworld.org/forums/c-class-w...placement.html

There's another related thread here:
https://mbworld.org/forums/c-class-w...ml#post4520519

Glyn M Ruck

Casper - thanks so much for the clarification. I hate giving bum information. The RHD cars must have a different harness to LHD ones.

casper_c230

Yup, thanks for your contributions. Always appreciated!

2subway

Hi all, I have to order both up and downstream O2 Sensors. I read through this thread and all it did was confuse me as to which sensors I need to order. I noticed that the harnesses for each sensor are different. Does anybody have the actual part numbers for the correct sensors that I need for my 2003 C230 Sedan. I just don't want to order a sensor that will arrive with the cord too short. THANKS