Possible causes – Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1– Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 harness is open shorted to ground– Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit poor electrical connection– Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit fuse– Faulty Engine Control Module (ECM) When is…