Hi,

You guys know if there was any way I could have triggered a P0138 (2nd O2 sensor high voltage) by goofing up a yellowbox install? I followed the DIY for yellowbox install but mistakenly tried to splice into the blue/white on the wrong side of the C101 (light blue box). I had to unplug the blue ECM and gray ECM cable to get at that wrong side and attempted to start the car with those cables unplugged by mistake. I fixed my mistake and correctly spliced into the blue/white on the other side of C101 closer to the door and the yellow box seems to be working correctly, but now I got a P0138. I hooked up an OBD2 reader and saw that the voltage varied from 1.0 to 1.2. Before I go replacing a $200 oxygen sensor anyone have any suggestions? Thanks.

 

anyone?

 

Have you cleared the DTC and it recodes?

Did you splice into any other wire besides the blue/white?

 

Yes, I cleared with an OBD2 reader after pulling the code and it (p0138) came back about a week later. I pulled open the kick panel and checked all the wiring visually as best I could and everything seemed ok. I've ordered an OE type oxygen sensor ($70) to check if was just a coincidence that the sensor went bad as I was doing the yellowbox install. Figure I pop it in and if the volts are still at 1.2 then I have a wiring problem.

No, in regards to splicing any other wire... I try to keep my car as stock as possible. I'm still using the stock stereo system =p.

Is there any way I could have just shorted the sensor during install? I'm just worried that the problem is still there with the new sensor.

Thanks.

 

Well first of all you should have disconnected the negative terminal from the battery when you do any kind of electrical work on a car. But you shouldn't have been able to short any systems by simply splicing some wires, I haven't looked through the yellow box install, but is there any way you could have pulled or crimped/cut the wire going to the o2 sensor? Since it took a week to come back I would guess either the sensor just happened to go bad at the same time, or you somehow damaged the insulation on the wire during the install, causing it to ground intermittently against a body panel.

 

"you somehow damaged the insulation on the wire during the install, causing it to ground intermittently against a body panel. "

that could be... I saw that a couple wires had tiny chips on the surface of the wire covering but definately not deep at all. When I had the kick panel open... I left the OBD2 reader in live update mode and read the volts of the O2 sensor as I played with the wiring (moving it around etc) and no change. I did solder the yellowbox wiring on and was very careful about it.

I didn't know about disconnecting the battery for electrical work. Also, any idea which wire in the kick panel goes to the rear O2 sensor? Thanks for all the good info =).

 

Another thing is I grounded the yellowbox on the bottom nut closest to the front of the car holding the ecm in place. Is that ok?