Rear O2 code (CEL)
Thread Starter
Instructor
Joined: Aug 2009
Posts: 234
Likes: 15
From: Fall City WA
Rear O2 code (CEL)
I recently had a dyno tune that disabled my rear oxygen sensors. No CEL light on the trip, however yesterday, after about 30 minutes of driving it came back on. I read somewhere that the ECM has to go through 3 warm up cycles before it will stop displaying a CEL. Is that true?
The code was P0136, which indicates driver's side. There was no other code, which surprised me. I expected to see a similar code for the passenger side. Is it possible the driver's side 02 sensor is plugged into the rear plug? When I had the tune done, all 4 sensors were in place. After the tune, I removed the rears.
The code was P0136, which indicates driver's side. There was no other code, which surprised me. I expected to see a similar code for the passenger side. Is it possible the driver's side 02 sensor is plugged into the rear plug? When I had the tune done, all 4 sensors were in place. After the tune, I removed the rears.
Thread Starter
Instructor
Joined: Aug 2009
Posts: 234
Likes: 15
From: Fall City WA
What I meant to ask about the 02 sensor connections is are the main & rear plugs the same? Could I have mixed front and rear? I don't have access to the car right now, so just wondering if someone knows that.
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
I recently had a dyno tune that disabled my rear oxygen sensors. No CEL light on the trip, however yesterday, after about 30 minutes of driving it came back on. I read somewhere that the ECM has to go through 3 warm up cycles before it will stop displaying a CEL. Is that true?
The code was P0136, which indicates driver's side. There was no other code, which surprised me. I expected to see a similar code for the passenger side. Is it possible the driver's side 02 sensor is plugged into the rear plug? When I had the tune done, all 4 sensors were in place. After the tune, I removed the rears.
The code was P0136, which indicates driver's side. There was no other code, which surprised me. I expected to see a similar code for the passenger side. Is it possible the driver's side 02 sensor is plugged into the rear plug? When I had the tune done, all 4 sensors were in place. After the tune, I removed the rears.
Not exactly sure what you are asking here but if you removed the rear O2's how could one of them be plugged into either side? Of course the rear 02's are mainly there to check converter efficiency so I don't know why your tuner did not just turn them off to the MIL altogether? And as for your other question, yes the ECM normally has to see a fault/no fault for 3 drive cycles to activate/turn off the MIL light. But just have them turned off completely problem solved.
Thread Starter
Instructor
Joined: Aug 2009
Posts: 234
Likes: 15
From: Fall City WA
The rear o2's were disabled, well, should have been. I wasn't asking about mixing up the connections left to right, but rather front to back. Is it possible to have connected the front 02 sensor to the rear connector, and rear sensor to the front connector? And when I removed the rear 02 sensors (after tune), that effectively removed the main sensor? I don't remember if the connectors are different between front & rear. From the code I pulled, it's only complaining about 1 bank.
