Code P0031 Possible Causes
Heated Oxygen Sensor Bank 1 Sensor 1 circuit fuse
Heated Oxygen Sensor Bank 1 Sensor 1 circuit poor electrical connection
Heated Oxygen Sensor Bank 1 Sensor 1 harness is open shorted to ground
Faulty Engine Control Module ECM
Faulty Heated Oxygen Sensor H2OS Bank 1 Sensor 1