P0133, but only while in 4WD

bighedder

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06 TJ, DTC P0133 only when in 4WD. In 2WD, no codes. Any ideas??


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Sounds like a ground issue. I'm sure somebody more familiar with the circuit will be able to help guide you to the location.
 
Are you saying though that if you clear the code and never put it in 4WD, the code doesn't appear? But the moment you put it in 4WD, the code shows up?
 
That is an 02 sensor code.
Does your engine have over 100k? When those sensors start throwing 02 codes they dont care whether you are in 4wd or not.
Can't tell you why yours is acting the way it is.
That code also shows up when your precats are beginning to fail so watch for that.
 
Are you saying though that if you clear the code and never put it in 4WD, the code doesn't appear? But the moment you put it in 4WD, the code shows up?

Yes that’s correct but not right that moment once in 4WD. 125k. I think I found comments about folks hitting the trails, getting the CEL but once back to 2WD the light goes away. I’ve already replaced the O2 Sensor B1S1


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Yes that’s correct but not right that moment once in 4WD. 125k. I think I found comments about folks hitting the trails, getting the CEL but once back to 2WD the light goes away. I’ve already replaced the O2 Sensor B1S1


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Did you replace the sensor with a NGK / NTK brand sensor?
 
Sure did, using your guide [emoji1303]


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Okay, so at least you know it's not that.

I found this:

Common problems that trigger a P0133 code:
  • Defective oxygen sensor/air fuel ratio sensor
  • Defective oxygen sensor/air fuel ratio sensor heater circuit
  • Exhaust system leak
  • Intake air system leak
  • Low fuel pressure
  • Defective engine coolant temperature sensor
  • Defective sensor wiring and/or circuit problem
  • PCM software needs to be updated
  • Defective PCM
It still doesn't make much sense that it only happens when you put it in 4WD though. That seems awfully coincidental perhaps.

Maybe check the wiring going to that O2 sensor and see if there are any exposed / worn wires?
 
Okay, so at least you know it's not that.

I found this:

Common problems that trigger a P0133 code:
  • Defective oxygen sensor/air fuel ratio sensor
  • Defective oxygen sensor/air fuel ratio sensor heater circuit
  • Exhaust system leak
  • Intake air system leak
  • Low fuel pressure
  • Defective engine coolant temperature sensor
  • Defective sensor wiring and/or circuit problem
  • PCM software needs to be updated
  • Defective PCM
It still doesn't make much sense that it only happens when you put it in 4WD though. That seems awfully coincidental perhaps.

Maybe check the wiring going to that O2 sensor and see if there are any exposed / worn wires?

Thanks Chris. Curious about the PCM, how can I tell it’s been updated or needs updating and what would the dealership charge for that? The thing is the tj runs great, no idle or misfire issues, no loss of power or any crazy noise from the engine. I did go back and trace the O2 Sensor wires back to the PCM and unplugged the connectors, took a vacuum to them for the dust/dirt and then reconnected. I’ll have to continue watching


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Thanks Chris. Curious about the PCM, how can I tell it’s been updated or needs updating and what would the dealership charge for that? The thing is the tj runs great, no idle or misfire issues, no loss of power or any crazy noise from the engine. I did go back and trace the O2 Sensor wires back to the PCM and unplugged the connectors, took a vacuum to them for the dust/dirt and then reconnected. I’ll have to continue watching


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The first trick would be finding a dealership that could actually update it for you, let alone be willing to work on it. Since parts are no longer in production for TJs, most dealers won't even work on them at all. However, if you call around to 5 or 6 local dealers, you'll eventually find one who will have a master tech there who has been around long enough that he can work on it.

Not sure what they would charge, not even the slightest clue. But they would be able to scan it and tell you what's going on. I personally highly doubt it's the PCM. Usually when that happens, there's way more going on than what you are experiencing.
 
I think the rear most O2 sensor loom runs over the transfer case. Is it possible when you shift that the linkage has damaged the wiring over time?
 
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I think the rear most O2 sensor loom runs over the transfer case. Is it possible when you shift that the linkage has damaged the wiring over time?

Funny, I found the B1S2 was covered with oil (garage oil change). I had cleaned it off so it could breathe. No CEL so far.


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