Haven't been here in a while because you all helped me resolve any past issues..but now I have another unfortunately. My check engine light came on a few days ago so I ran it by Auto Zone to see if they could get a code on it. It came back with "the ECM has detected a fault with the downstream 02 sensor. Probable cause..check other service codes first...next it says check leak near 02 sensor..then failed 02 sensor..and lastly it says fuel contamination. So I took it to our mechanic and after having it for several day with the last being today because he said he need the car to be cold to do whatever he was going to do. He called to say that there is nothing wrong with the car and he thinks that maybe something or other needs to be recalibrated or updated and I need to take it to a dealer who is capable of doing that. So..I'm coming to the place where I know I will get great advice and I thank you in advance!

 

The O2 sensors get flaky with age - I'd change the sensor (around $100 for the part and maybe an hour labor).

And don't go near a dealership with that car, I suggest (and have done this), that you find a local shop known for their work on Mercedes products for times like this.

Next time, try to get the EXACT P-code is it throwing - Autozone will usually read them for free. We can then go from there.

 

I did go to autozone..It looks like the P code is P2098 ..I'm sorry I should have included it and that's EXACTLY what I told my mechanic..that I didn't want to take it to a dealership because I'd probably walk away with more problems and is why I am here instead of there :-) I'm in Cypress, Texas 77433 if anyone knows someone to refer me to that would be awesome and very much appreciated.

 

I still say I'd change the O2 sensor - your car is (not sure what year it is) 8-10 years old - O2 sensors don't last forever.
If the car is running fine, getting the same mileage, not throwing other codes - then other than a bad connection between the harness and the O2 sensor it is most likely the sensor is about done.

And even IF it is a bad connection, changing the sensor means one half of the connection is replaced with the new sensor (and I don't think it's a bad connection, but you never know.)

 

So did you have the code cleared? Did the light come back on?

 

The car is an '05 and those are the only codes, running fine and have not noticed a difference in the mileage I'm getting. They did not clear the code so the check engine light is still on. I have a Drivers Auto up the street who works on foreign cars and I'll assume that's where I should head since it's the Mercedes engine. I can check to see if they can clear the code first and see what happens and talk to them about the 02 sensor being replaced as well as checking the harness.

 

They did not clear the code so I can go by someone else to see if they can do that for me. We have the same car! I cant find my touchup paint and I'm not sure if this is the only color red it came out in. I found a site that said you can tell from looking at the door jamb but mine doesn't read the same as what the site said. Any chance you know which touchup paint number I would need to get? If the crossfire only came out in one red color then it simplifies that.

 

Shouldn't my mechanic have been able to tell if the 02 sensor was bad when the checked the car? He knew the code that was thrown was saying it was the 02 sensor.

 

There was only one red color in 2005.

 

Thank you for that info zeracer!

 

Paint codes are here.

 

This where it is handy to have an Android device (phone or tab), OBD-II dongle, and Torque Pro: The secondary O2 sensors should both read about .6v when lit off, they just verify that the catalyst is doing its job. Unlike the pre-catalyst O2 sensors they do not transition much.

For me that is as much a part of my on-board tool kit as a lug wrench....errr assuming we had a spare tire.


ps if I were getting that, I'd swap the two secondary O2 sensors side to side and see if the code follows. If not you may have a different problem.

 

First thing I would do is fill the tank with the best gas you can find locally. At the same time put a bottle of gas conditioner or Techron with the gas. Write down all the codes then have them totally cleared. Drive the car until the light comes back on again. If the light comes back on, then you know the problem still exists and have it diagnosed again by someone that can help you.

James


PS As I am told two different names were used for red over the years. They are the same red as the paint codes for both of them were the same. Blaze Red and Inferno Red.

 

I think the place I get my gas normally has that additive you can pay extra for so it's added while you are filling your tank. I'm sure my mechanic will clear the codes for me and then if it comes back on after driving it I will take it by Auto Zone again and see if it throws the same code. Drivers Auto told me today that they could handle fixing it. They've done good work on some of our other vehicles so far but are more expensive than my regular mechanic who also does great work but can't figure this one out because he doesn't find a problem with the o2 sensor or anything related to it. Also..thanks for the notice on the colors because I saw two which gave me pause after you saying there was only one.

 

I went by my mechanic to have him clear the P2098 code on my car and also discussed the 02 sensor and he said they checked it twice and it is not an 02 sensor problem so not sure what to do now. I did go fill my car with Exxon V-power fuel. Does it have a conditioner or techron in it or do I still need to add to the the gas tank?

 

You can add a conditioner if you like. I figured it wouldn't hurt anything if you had some bad gas in the tank, which could trigger an 02 sensor code. Start with the simple and obvious things first.

James

 

Makes sense and hopefully that's it!

 

Vacuum leaks can also throw lean/rich codes. Visually and manually verify all the vacuum lines are intact. You may need to find a garage that can do online/running diagnostics to determine where the problem lies.

 

I show the following for a P2098:
- Faulty Heated Oxygen Sensor
- Heated Oxygen Sensor harness is open or shorted
- Heated Oxygen Sensor circuit poor electrical connection
- Exhaust leaks
- Contaminated Heated Oxygen Sensor
Read more: http://engine-codes.com/p2098_chrysler.html#ixzz3AzUKUU1p

but again I'd just select the O2 sensor page on my cell phone and monitor them while driving. You have seen the first page before but my display is best with six parameters so I have several pages. This is the O2 sensor and fuel trim page.

The 1x1 and 2x1 (lead bank 1 and bank 2) are transitioning but the secondary sensors (1x2 & 2x2) are both reading mid scale right where they are supposed to be.

Key is they should both be between ,5 and .6 anything greater or less would mean something is wonkey but monitoring these while fully wamed up is the only way to diagnose the problem. Anything else is just throwing parts at it. (/rant)

Unfortunately too many mechs and including some really good ones have trouble using proper instrumentation.

 

James I wanted to get back with you and let you know that I did fill the tank with premium *as always* gas at an Exxon, as you suggested after I had the code cleared and it hasn't come back on. I can't find the date for this conversation but I'm pretty sure it's been 2-3 weeks so can I assume that that was the problem?