Possible causes

– Faulty Heated Oxygen Sensor Bank 1 Sensor 1
– Heated Oxygen Sensor Bank 1 Sensor 1 harness is open or shorted
– Heated Oxygen Sensor Bank 1 Sensor 1 circuit poor electrical connection

When is the code detected?

Heater current requirements too low or high in the heated oxygen sensor (HO2S) heater control circuit

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)