Possible causes

– Faulty heated oxygen sensor
– Heated oxygen sensor harness open or shorted
– Heated oxygen sensor circuit poor connection
– Faulty heated oxygen sensor relay
– Faulty Engine Control Module (ECM)

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)