# P0136: What Next?



## Josh (Aug 7, 2004)

I usually pop the check engine light every 3,000 miles with the following code:
P0136 02 Sensor Circuit Malfunction. (Bank 1. Sensor 2).

In the past I always just reset it and kept on driving. 

Should I change the oxygen sensor or not?
When I went to Kragens they asked me if I wanted to change it before or after the catalytic converter? 

Any suggestions? I want to do the right thing? Not sure what to do . . .?

ORIGINAL OWNER: 136,000 MILES
1997 NISSAN SENTRA 
GA16DE 

Thanks.
Josh


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## khager (May 9, 2011)

I have this exact same code on my 95 Sentra. Where is this O2 sensor located? I want to change it so that I will start getting good gas mileage again. Does anyone know where this is located? On cat or behind? I don't know if I need to buy the downstream or upstream O2 sensor.
Thanks!
Kristal


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## smj999smj (Jan 1, 2006)

P0136 is for the rear, or "downstream," oxygen sensor located behind the catalytic converter. 99% of the time if this code triggers---and assuming you don't have any exhaust leaks---it is the sensor itself that is bad. NTK is the OEM sensor and I would recommend sticking with NTK or Denso for the replacement part; Rockauto usually has pretty good prices on them. The rear sensor is used only for catalyst monitoring and has no affect on engine performance, so it has no affect on gas mileage.


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## khager (May 9, 2011)

Thank you!


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