o2 sensor code 95 e320 - PeachParts Mercedes-Benz Forum

lee polowczuk · #1 09-06-2010, 02:01 PM

I just bought a code reader for my fleet. the e320 has 136k on it and is running great. get about 22 mpg in combined highway, city driving...probably 70 percent city.

anyway.. i attach the code reader...and get only one code..... the o2 sensor apparently is not working up to snuff.

no CEL light, good mileage.

maybe i will just replace it as a maintenance item.

Can't Know · #2 09-06-2010, 02:07 PM

Boy, I sure would. The things get old and close to out of range and will trigger codes but often not a CEL. Bosch says to test or replace them at 100K so you're well beyond that and you're likely to see an improvement in economy and maybe performance. If you wait to the CEL they are basically not functioning at all. It may be pretty tight, if you can't break it loose try getting the car hot and then see if it will start to loosen. If so just get it loose a turn and let the car cool down before you remove and replace it. If it's still very tight after you get it hot then let it cool and try again in five-minute increments. The different rates at which the parts cool can help to get it loose.

lee polowczuk · #3 09-06-2010, 03:36 PM

Quote:

Originally Posted by Can't Know

Boy, I sure would. The things get old and close to out of range and will trigger codes but often not a CEL. Bosch says to test or replace them at 100K so you're well beyond that and you're likely to see an improvement in economy and maybe performance. If you wait to the CEL they are basically not functioning at all. It may be pretty tight, if you can't break it loose try getting the car hot and then see if it will start to loosen. If so just get it loose a turn and let the car cool down before you remove and replace it. If it's still very tight after you get it hot then let it cool and try again in five-minute increments. The different rates at which the parts cool can help to get it loose.

i've replaced one several years ago.... believe it or not....it came right out..

go figure... i guess i have to get a bosch generic 4 wire...

EricSilver · #4 09-06-2010, 04:01 PM

Also check under the passenger carpet to make sure the wires are not simply corroded.

gregs210 · #5 09-06-2010, 04:13 PM

Eric makes a good point, always worth checking that stuff. Still, at that mileage I'm with can't know, I'd just change it.

That said, the cost difference is only $15 at the place in Aridzona (********, $75 vs $90) for the direct fit plug in. Considering the wire run and splice time, I'd probably lean towards the direct fit. When I replaced mine the cost difference was substantial (about $50 each) and there were four, so I did the splice 'n dice thing.

They can be strange to change. I've done some where they slid right out (you think wow, that's some good anti-seize compound!) and others that I'd swear someone tack-welded after tightening to like 150 ft. lbs.

Either way if the car's otherwise sound it's worth changing it for the small sum. Just curious, have you had any of the harness issues?

deanyel · #6 09-06-2010, 05:54 PM

You got what code number, on what PIN? An O2 sensor code on the DM should trigger a CE light.

lee polowczuk · #7 09-08-2010, 11:51 AM

Code number 2 on pin 6

Heated oxygen sensor faulty.

lee polowczuk · #8 09-08-2010, 11:54 AM

Quote:

Originally Posted by gregs210

Eric makes a good point, always worth checking that stuff. Still, at that mileage I'm with can't know, I'd just change it.

That said, the cost difference is only $15 at the place in Aridzona (********, $75 vs $90) for the direct fit plug in. Considering the wire run and splice time, I'd probably lean towards the direct fit. When I replaced mine the cost difference was substantial (about $50 each) and there were four, so I did the splice 'n dice thing.

They can be strange to change. I've done some where they slid right out (you think wow, that's some good anti-seize compound!) and others that I'd swear someone tack-welded after tightening to like 150 ft. lbs.

Either way if the car's otherwise sound it's worth changing it for the small sum. Just curious, have you had any of the harness issues?

I have a newer harness.... there's a "born on date" tag on a wire that leads to the batery... It says 22.05.98

There's also a design date....that's earlier..... if i knew someone at the dealer i am sure they could run the vin number and tell me when it was replaced....