W202, Obd P0133, P0136
 

On my 1998m 110K miles, C230, CEL went on & I got codes -
P0133 O2 Sensor malfunction slow response bank1 sensor1
P0136 02 Sensor Circuit malfunction bank 1 sensor 2


should I first change out the original oxygen sensor to see what happens?


Scott
baltimore

Update,

Got codes listed in previous post - and I replaced just the Oxygen Sensor and since then no more CEL. It has been two weeks since installing the new O2 .

Did need an O2 socket from Harbour Freight that cost five-dollars in order to unscrew the old sensor, easy.

The electrical connection end of the O2 sensor and the routing of the wire was the hardest part, but not bad.

Have noticed that with the new O2 sensor my car seems to start-up quicker.

Scott,
I hope that takes care of it for you. I've been fighting the exact same 2 codes for a while now on my 1997 C230 w/118k miles. I've replaced my upstream sensor twice; once with a universal sensor, and the code came back, so I replaced it with an OEM one... and the code still came back. It usually takes a few days for the code to reappear after I clear it. I've also tried cleaning the MAF, but if the code keeps coming back I might try replacing it. I'm running out of possible causes for P0133.

I just finished replacing my downstream sensor to see if that clears up the P0136. That was an absolute pain as I had to lower the exhaust system to squeeze the socket up there to get the sensor loose. I learned from another post that you can lower the back half of your exhaust system easily because it is only held up by hangers.

Charlie

Charlie,

Wow, I'll see what happens.
I did replace my MAF sensor approx 60K miles ago.

If my codes come back on, I'll probably go to a dealer and have it cured.
Then I'll post what they do.

I believe that replacing the O2 sensor will normally cure a P0133, so I think mine is the exception. I hope that fixed it on your car. Good luck!

It just seems odd to me that both sensors would go bad at the same time. I wonder if one of those codes is a false alarm or if the problem actually lies elsewhere. Have you searched by those code #'s?

Yes, I've searched around, but haven't found anyone else with the exact same problem (except here). My P0136 was a pending code, and only occasionally has triggered the CEL. I think since it was pending it went unnoticed for a while, so it might have been happening before the P0133 and I never knew it.

Got my code back the one for the oxygen sensor P0133 - so my O2 sensor change didn't fix the problem. ( may have gotten the second P0136 also, I don't remember what the Autozone employee pulled )

In the state I live in they have emission testing and I'm due for a test in mid October.

Will now go to the local MB dealer and have them fix it, I will post the repairs that they made.