post-oxygen sensor replacement.. - PeachParts Mercedes-Benz Forum

miktvk · #1 03-26-2003, 08:09 PM

I've been doing a complete search on all oxygen sensor related issues, but I just need a response to this one question:

After I replace the sensor, does the fuel/air mixture readjust itself back to healthy spec, or are there any further steps I need to take to make the car run correctly? Does clearing the #2 code do this for me. or...is there something more I need to do?

Thanks!

#2 03-26-2003, 09:56 PM

Hi,

As long as you didn't fool around with the mixture, it should be back at spec. Yes, you'll have to clear the code.

Regards,

miktvk · #3 03-27-2003, 10:39 AM

thanks, that's what I was thinking.

Arthur Dalton · #4 03-27-2003, 11:58 AM

Your car is HFM-SFI . You couldn't fool with the mixture if you wanted too.. It is non-adjustable .
It will adjust itself..

miktvk · #5 03-27-2003, 12:03 PM

Thanks, Arthur!

The reason I ask is that my indy is asking $470 for diagnosis-replacement-recheck system!!!

It's a bit tight right now, so I was just about floored when he gave me this estimate. I'm gonna pay him for diagnostic time, then wish him good day, replace it myself, then reset codes.

90% sure this will fix CE light, sluggish accel. and poor MPG.

Yikes!

suginami · #6 03-27-2003, 05:04 PM

I think you might need to find a new mechanic.

$470 for what?

If you still have a CE light illuminated, you can clear it yourself in about 6-8 seconds.

stevebfl · #7 03-27-2003, 05:17 PM

The O2 sensor is a reasonable replacement item as it often is stated to be replaced at 60k miles anyway. We never do it because its function is so easily tested, but often will when there is such a code and the miles are right.

The most important thing to watch when dealing with O2 sensor codes is the adaptation numbers. These should change if the sensor was a problem.

miktvk · #8 03-29-2003, 09:38 AM

Thanks Paul and Steve,
At 112K, I think its time for this item to be replaced, which leads me to my next issue:

Wow! This is ONE TOUGH nut, how the heck do I get this thing loose without stripping it or snapping it right off?

I tried yesterday using combo of penetrating oil(soaked for about 4 hours) and warming up the pipes, but no go. It was so tight that my sensor remove socket actually slipped, rounding off the corners somewhat, but not a lost cause yet.

So I let it sit all night with pen. oil on it and going to try again today. Should I just decapitate the old one so I can get a shallow 22mm socket on it or...what?

miktvk · #9 03-29-2003, 12:00 PM

Am I the only one to have had so much trouble extracting the sensor?

Any advice much appreciated...