Possible causes – HO2S Bank 1 and 2 Sensor 1 harness is open or shorted– HO2S Bank 1 and 2 Sensor 1 circuit connectors (wrong connection)– Faulty Engine Control Module (ECM) Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P0040 VOLKSWAGEN OBD Code Description The heated oxygen sensor (HO2S) monitor determines if…