I must say again, This I couldn't believe, neither could my mechanic... Not sure if anyone has ever heard of this but it is an advantage to know if it happens in the future.

I bought my CLK about 6 months ago so it was just coming up on the end of the warranty when the engine management light came on, I brought it to my mechanic and he plugged it in and it read "O2 sensor fault low voltage (Sensor 1 Bank 1)" seemed straight forward, or so we thought.

He rang the local main Merc dealership to check which sensor it was, they said that it's the one before the Cat but then he said something a bit worrying.

He said "When you disconnect it check and see if there is oil in the connection, if there is then the cam shaft sensor is gone which has allowed oil to run through the whole wiring loom feeding the sensors of the engine".

As you can imagine I went out to get it checked and seen with my own eyes the oil in the connection. As luck would have it I brought it back to where I bought it, at first they didn't believe me, they peeled back the protection on the wires and they were clean, but then another dealership in the same town got the same problem.

What actually happens is that when the sensor fails it doesn't register because it allows oil to seep through the actual copper of the wire so it cant send a fault signal. also because it's through the core of the wire it looks clean when stripped.

At the moment there's a new Cam shaft positioning sensor gone in and a new wiring loom and O2 sensor has been ordered. I think there's another part ordered and when I find out I'll tell yee.

Preventative action... I do believe that they've developed a connection that fits at the Cam shaft sensor that if the sensor fails, it stops it from going any further but alas it wasn't on mine. It seems it this model and years are proned to it... Mines a 01 and between the other dealerships I've asked I've found 5 others that were 2000 or 2001...

I'll keep you posted on my progress...

All I can say is Thank God for warranties...

 

This is good info but I am confused as to the exact issue or problem. Could you please provide us some pics of the problem or where the oil seeps out from? Thanks for sharing this info!!

Greg

 

Sound, I'm waiting on the parts at the moment but when they arrive i'll see if I can get a few pics while they're doing the job and i'll get some more detail on it...

 

Great thanks!!

 

I'm still trying to figure out why the mechanic had to call the dealership to see which sensor "Sensor 1 Bank 1". That's very basic info.

 

This is true but to give him the benefit of the doubt maybe he was just double checking before he changed anything out. Either way he ended up getting good info on what to look for so he did well on that part.

Greg

 

Very true! At least he found the issue.

 

Yep, exactly. He wanted to double check for me because it wasn't going to be himself that was going to be replacing it so I had to be sure of the part, the garage I bought it off was going to replace it for FREE (wohoo) so I had to be sure it was the right one and not be going back a week later with my tail between my legs saying it was the wrong one...lol...

It's an hour and a half drive away so its easier to just bring it out to my mechanic to check.

Waiting on the parts still, hopefully the end of this week or next week at the latest, will keep you posted.