Emission Code P0136

[ahess77]

Anybody have any insight as to why I'm getting code P0136 Oxygen Sensor Circuit (Bank 1 Sensor 2)?

Let me know if you've had this before. I've got 31k miles, the check engine light came on while I was driving, not at start-up.

Thanks.

[KillJoy]

Bad Sensor?

KillJoy

[RF Overlord]

If memory serves, Bank 1 Sensor 2 is the rear O2 on the passenger side. The rear O2s just monitor catalyst efficiency, so maybe you have a bad cat. The good news is whether it's the sensor or the cat, they're both covered under the 8/80 emissions warranty.

[shakes_26]

ooh oooh i know I know..... :rolleyes:

I have this code on my 97 explorer right now.

P0136 is bank1 sensor 2, so its the passgr side rear (after cats) sensor. This code is either a bad sensor, exhaust leak, damaged sensor, disconnected sensor, damaged/melted wire to sensor.

Have fun.

BTW all OBD II systems use the same codes so whats good for the Exploder is good for the MM.



Anybody have any insight as to why I'm getting code P0136 Oxygen Sensor Circuit (Bank 1 Sensor 2)?

Let me know if you've had this before. I've got 31k miles, the check engine light came on while I was driving, not at start-up.

Thanks.

[SID210SA]

I had an emissions code (dont remember the number) but it ended up being my gas cap wasn't sealing properly.

[JACook]

I had an emissions code (dont remember the number) but it ended up being my gas cap wasn't sealing properly.
That would have been a P0442 or P0455, depending on how loose the cap was.

shakes_26 has it nailed, with the possible exception of the part about the exhaust leak.
The only thing to add here, is that the P0136 can not be caused by a catalyst.
It's an electrical malfunction in the O2 sensor and/or circuit itself.
Catalyst efficiency problems will show up as a P042x or P043x error.

[ahess77]

Thanks for the responses, but I think I found the problem.
I cleared the code and drove this weekend. The car has been stumbling occasionally in the past week, I'm blaming a bad tank of Sunoco. So, during one of the episodes this weekend, the check engine light came on again. Same code. So now I think it's throwing that code at low voltage. That sensor may be the one that's most successible to low voltage, or the computer pics that code first at low voltage, or something like that. Anyway, I'm hoping it goes away on it's own.

My other obvious choise is that the sensor is causing the engine to stumble which will certainly require me to find a dealer for repair where my car won't get stolen again.

Let me know if you've seen anything similar, I'm running a tune from Lidio.

[RF Overlord]

I'm running a tune from Lidio.I thought all of Lidio's tunes shut the rear sensors off... :confused: Also, I don't think a rear sensor can cause a stumble...

[n-cherok]

Ive had that code before it comes on every 6k miles or so, usually just clear codes and its fine.

[shakes_26]

I crawled under the Explorer this weekend (same code p0136). It had been coming on here and there I would reset, week or so later, sometimes a few miles later.

Anyway, crawled under the truck, and low and behold, the wire harness for the O2 was melted, had been laying on the exhaust pipe. Patched it up, zip tie here and there, should be good as new.

I'd be looking under there, make sure you have no melted wire harness. Have you had any work done recently?

Lidio's tune does ignore the rear o2 sensors, but I'm not sure the circuit is disabled. That is to say, a short circuit may still throw a code, but out of range o2 values are no longer flagged. Thats just a theory mind you as I don't have the emissions book for our cars and not sure what the tuners actually are 'turning off'.


Thanks for the responses, but I think I found the problem.
Anyway, I'm hoping it goes away on it's own.

Let me know if you've seen anything similar, I'm running a tune from Lidio.

[wchain]

P0136 Should be covered by the cars 8yr/80K Federal Emissions Warranty.

[JACook]

Thanks for the responses, but I think I found the problem.
I cleared the code and drove this weekend. The car has been stumbling occasionally in the past week, I'm blaming a bad tank of Sunoco.
P0136 can not be caused by a bad tank of fuel, nor can it be caused by, or cause, a stumble.
As I said, P0136 is an electrical failure in the O2 sensor circuit. In this case, to the rear sensor on the
passenger side. This sensor's only purpose in life is to tell you if your catalyst is dying, or has died. It
does not control anything. You could have a bad sensor, or it could be wiring damage like what shakes_26
found on his Exploder. Either way, as Wes pointed out, it's covered under the emissions warranty.

As for whether Lidio's tune turns off this error, well, QED.