So, I was working on a buddy's car today that had a CEL #41 (primary O2). The problem is that he's already replaced it with a new sensor and the CEL is still there. I did a couple diagnostic checks like resetting the ECU, checking all fuses and we even tried another O2 sensor that I had laying around, but I know is good. It still threw the code. I had him unplug the secondary O2 sensor and it did throw the other code so it was checking the system.

I even rewired the O2 sensor because it was a Bosch replacement with this wacky connector on it. I know the wires are right and it really bothers me that we tried a sensor that we knew was good and it still threw the code.

Any ideas?

 

Sounds like a faulty ECU. You need a dealer type diagnostic computer. Maybe the ECU is considered and emissions device and will be covered under the 100k mile emissions warranty. is it possible he did some wiring like an air/fuel guage and has short somewhere?

 

nope, the only mods on the car right now are the suspension (skunk2 c/os & koni yellows), rims, header and AEM CAI. He and I installed everything together so I know it's done right.

I was wondering if maybe it's one of those weird OBD2 things where the dealer has to turn the code off. :thinking:

I'm actually pretty pissed that I couldn't figure this one out on my own.

 

Yeah, it may be fine, it just might need a good reset. Take it to autozone and see if their diagnostic machine will reset it.

 

I hope so, because I have been looking at the CEL for a couple of months now, and nothing I or Josh (westcoast) has done seems to help. Plus I ran over a tire that flew off a semi the other day and tore up my back bumper, so something else that needs fixed....