So I was recently tackling some O2 sensor codes because my vehicle registration was due and I had to get rid of the check engine light. In the process, I noticed the factory service manual actually has the wrong ECM harness pinouts for all the O2 sensor signal wires.

Per the FSM, the signal wire for Sensor2 Bank1 is pin#74. And Sensor2 Bank2 is pin #55. Here is a pic of the FSM:





And here are pics of the ECM harness from my car. You can see that there are no pins at spots 74 and 55.






I couldn’t believe they would make an error like this in the FSM.

So I grabbed my multimeter and started chasing wires to find the correct pinouts for all the O2 sensor signal wires. Here they are in case anyone needs them:

Bank1 Sensor1 (Passenger Front): Pin#73 =White wire
Bank1 Sensor2 (Passenger Rear): Pin#17 =Blue/black wire
Bank2 Sensor1 (Driver Front): Pin#19 =White wire
Bank2 Sensor2 (Driver Rear): Pin#36 =Red/yellow wire


My car is a 2005 coupe and I compared my FSM to that of the 03-04 and 06-07 and they all show the same pinouts, so I’m assuming those are wrong too. If any of you guys with an 03-04 or 06-07 ever get a chance to look at your ECM harness, please confirm if your pinouts are actually correct or not.

 

Mods, I wasnt sure where to post this on the forum. Feel free to move it around if its in the wrong place.

 

Wow, good info. This should be a sticky. I ran across an error like this a while back while trying to help someone here, except on a different connector. The ECU harness connector on my '04 coupe matches yours.

 

Wow that's weird, my 2006 rev-up has the correct pin layout.

 

So your harness actually has pins at spots 74 and 55?

 

I just felt behind it with my hand and the 4th and 8th slots on that row both have wires yeah. Didn't disconnect it or check colors or anything..