# Air fuel sensor bank 1 code



## creel228 (Oct 22, 2015)

I have an 04 Altima that is showing two different codes, 1031 and 1148, which both say air fuel sensor bank 1. First of all is this the O2 sensor that's located on the front of the engine on the exhaust manifold? Because I replaced my exhaust manifold and that sensor back about 6 months ago. Thanks for any help


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## rogoman (Dec 16, 2004)

Sensor #1 is located on the exhaust manifold, on top of the CAT. A P1031 code indicates that the harness or connectors for the sensor heater circuit is open or shorted. Also the sensor heater itself may be defective. P1148 is a related code to the P1031 that is described as a "Closed loop control function" not operable; if you fix the P1031, then the other code should go away.

When replacing emission devices, stay with OEM, not some unknown aftermarket device.


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## creel228 (Oct 22, 2015)

That might be my problem then because I replaced the O2 sensor with an aftermarket one because of the price.


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