Oxygen Sensor Replacement '95 S320?
 

My check engine light is on and the shop told me it's an error for the oxygen sensor. I don't have the exact error number.
My car has 165k miles now and I have never replaced an oxygen sensor nor have I seen it in the maintenance records. The car has several intermittend problems right now:
- sometimes the idle fluctuates
- sometimes almost no power at "take off" (for a second or two)
- vibration coming from the engine when decelerating at highway speeds
I have a couple of questions:
- Could these problems be related to the oxygen sensor?
- Is there one or two sensors on the S320?
- How do I change them?
- Is it hard to do?
- How much do they (it) cost?
Thank,
Sab.

It is not difficult and the sensors are in the range of $100 to $150.

Check the wiring at the connector before replacing it. The code is set the same for a wiring problem as it is for a bad sensor.

Good luck,

As far as O2 sensor is concerned, it should be replaced every 60,000 miles. This is from my 95 E420 maintenance manual.

One tip: apply hot lubricate paste (MB part # 000 989 76 51) on thread of lamda sensor.

good luck

I saw one of the sensors the other day when I looked. I assume there are two. Does someone have part numbers I would need to replace it all.
Thanks,
Sab.

ALLDATA shows one part number 0005405517 for $158 and 1/2 hr labor.

The schematic shows 2 sensor locations, one before the cat and one after. Your code may have indicated which one was malfunctioning.

Thanks for the help guys, I finally changed both sensors. I got them for $113 rear and $119 front and the exchange took only a couple of minutes.
Can I reset the check engine light or do I need to go to a shop to have it reset?
cheers,
Sab.

With almost 180K miles on my C280, I have never replaced the O2 sensor. That being said,you, have to realize that MB's are known for their lack of required maintenace. I suggest you try an independent shop that does foreign cars as this is an easy job. Warning, don't take it to a dealer becuse they will find many things that need attention and you will spend a lot of money with them. Also most dealers simply do not know how to work on a MB. P.S. My car runs just like it was new and it has never seen a dealer. Oh, at 100K miles I put a set of Champion Platinum plugs in even though the (OEM) plugs seemed perfect..

Thanks Peter,
but I did the swap already, the new O2 sensors are in. But I did have the check engine light on for a while now and I had the code checked which was indicating a faulty oxygen sensor.
How can I reset the light and clear all error codes?

Disconnect battery or press the led switch for 8 sec.

Disconnect the battery for about 5 min. Reconnect it , but beware, you will have to follow the instructions on resetting your radio. This is a simple task. Good luck. By the way, don't over maintain your car, 'cause it will only cause more problems. Treat it like a Chevy or Ford. These cars are not like magic blankets.

Kamal,
LED switch? Where would I find it? Just courious.

Peter,
I defenitely don't want to over maintain, but it hasn't been running right lately and the check engine light seemed to be caused by the O2 sensor(s), so I guess it was necessary.
The car is still not running as it used to, I get a intermittend surging idle condition and it sometimes has a real strange loss of power when trying to take off. But I guess that is going to be a new post.
Thanks all, regards,
Sab.

x11/21s1