|P0031 – HO2S Heater Control Circuit Low (Bank 1, Sensor 1)|
|Description: The powertrain control module (PCM) monitors the heater in the heated oxygen sensor (HO2S) for correct operation. The PCM controls the heater on and off duty cycle to maintain a calibrated temperature. The test fails when the sensor does not warm up to the required temperature in a calibrated amount of time. The test also fails when the PCM is not able to maintain the required temperature after the sensor is warm.
Possible Causes: • HO2S heater circuit short in the harness
• Incorrect connections
• Damaged or corroded terminals
• Exhaust temperature significantly higher than expected
• Damaged HO2S
Diagnostic Aids: Inspect the connectors for signs of damage, water ingress, or corrosion.