Possible causes – Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 harness is open shorted to ground– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit poor electrical connection– Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 circuit fuse– Faulty Engine Control Module (ECM) When is…