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P0135 O2 Sensor Heater Circuit Malfunction

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didn't find much doing a search so figured i'd start a new one. got this code on a 1998 Legacy GT. i accidentally ripped the wires out of the connector and, comparing them to another unit, reconnected and taped them up. the CEL was on before this and i never checked it, and was one after this as well, so i can't really tell if the issue was there before or not. this is Bank 1 Sensor 1 - is that the front sensor?

 

should swapping in another sensor fix this? and can anyone verify that's the front sensor?

You are probably due for another sensor anyway. The front sensor needs to be an OE sensor. Depending upon how you tore the wires, they will need soldering (if you splice them).

 

 

nipper

  • Author

the wires didn't tear, the pins pulled out of the connector.

you think that's the front sensor then? bank 1, sensor 1 or whatever? the front and rear do show up differently in the codes right?

L: DTC P0135: FRONT OXYGEN SENSOR HEATER CIRCUIT MALFUNCTION (FO2H) Two consecutive trips with fault

 

Are there any additional codes present? If not a new sensor should fix it, provided it's not a wiring issue. The troubleshooting procedure has you check a bunch or connections and resistances and stuff which ultimately ends in replacing the sensor.

 

The bank 1 sensor 1 stuff is the generic ODBII description. Some vehicles have two (or more?) front o2 and sometimes two (or more?) rear o2 sensors, hence the bank/sensor# stuff in the generic descriptions.

 

Yes, rear o2 sensor has it's own codes.

Some codes require multiple cycles without the fault before the code will clear. Have you started, run, and stopped the car at least 3 times after you repared the wiring?

 

Are you still getting the same code, or are you just looking at the CEL?

  • Author

same code. taped pins into connector and still getting the code. reset the code, restarted and it was clear. came back within one mile of driving (car was already warm). i'll probably replace it.

 

anyone know if rear and front are the same?

anyone know if EJ22 and EJ25 front O2's are the same? i'll find out tomorrow at the dealer, but if anyone knows, fire away.

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