O2 Sensor Replacement - Codes Wont Go Away!
 

Hello everybody,

I have a 2004 Chrysler T&C with the 3.3L V6 and 120k miles. The MIL came on, I did the key dance and got P0038, Bank 1, Position 2 02 Sensor Heater voltage out of range high. O2 sensors have never been replaced.

I googled, and despite wading through a sea of poor and disjointed information (sometimes I wonder if bots are doing some of those write-ups) I decided to replace the downstream O2 sensor. Pulled it out (it's an NTK) and did not see any obvious trauma. Replaced it with a Bosch as the dealership was closed today and it was all the local parts stores have on hand. Put it all back together today and started drive cycles. MIL would not go off. I thought disconnecting the battery and draining anything residual would wipe the DTC and turn off the MIL - it did not. I used a scan tool to clear the codes and turn off the MIL, but it came back on within seconds. The second time I cleared the code, the MIL never turned off. The codes are P0038 and P0038 (pending).

My thought is that even if it is a sensor fault, it would take the PCM one trip to logic that out, issue a DTC, and set the MIL, so I'm confused as to why the code can't even be cleared.

My next step is to try an OEM O2 sensor, but other than that I'd like to hear from some of you all. I read the service manual. At some point today on the internet I saw a flow chart for going at this issue systematically, but for the life of me I can't find it.

Thank you!

put the oem sensor in first then go from there

There's your problem >>>>> Found a TON of them with open heater circuit right out of the box. I can't tell you how many arguements i've had with customers and independent shops because they don't believe it. They always lose. This has been going on for at least 3 years and I am still running across them regularly.

I have heard about the Bosch O2 sensor problems right out of the box as well. Try a Denso or NTK if you don't want to get raped by the parts guy's at the dealer.

Okay, swapped out the O2 sensor for a factory part - same result. Clear the codes, start the car, MIL comes on almost immediately. Same codes thrown.

By this statement, one would assume you did your diagnostic tests already. Did you?

I think I have it figured out. With the hard fault I became suspicious of the wiring. (I don't have a tester here...First mistake). After carefully threading my hands in there, something I couldn't really see didn't feel right. I had to cut open the conduit to get at it. I found one severed and one frayed wire between the harness and the female connector. No idea how that would have happened. Cutting, stripping, splicing, and crimping in that space is a real pain. The MIL is out, no codes stored for now.

Yeah that's a bad place down there on the mount.