There are many diagnostic code pertaining to the Oxygen Sensor. P-0131 1/1 O2 SENSOR SHORTED TO GROUND, P-0132 1/1 O2 SENSOR SHORTED TO VOLTAGE, P-0133 1/1 O2 SENSOR SLOW RESPONSE, P-0135 1/1 O2 SENSOR HEATER FAILURE, P-0137 1/2 O2 SENSOR SHORTED TO GROUND, P-0138 1/2 O2 SENSOR SHORTED TO VOLTAGE, P-0139 1/2 OXYGEN SENSOR SLOW RESPONSE, P-0141 1/2 O2 SENSOR HEATER FAILURE.
Some of the above codes will require O2 sensor replacement while others will need further diagnosis. For your reference 1/1 pertains to the upstream senor, which may be located on the front of the converter of pipe between the engine and converter, 1/2 is downstream located on the pipe after the converter. O2 heater related codes are EMISSION related codes for cold engine starts and do not affect engine performance, however for passing an Emission test, the sensor will have to be replaced.