Possible causes – 1/1 And 2/1 O2 sensors harness is open or shorted– 1/1 And 2/1 O2 sensors circuit connectors (wrong connection)– Faulty Powertrain Control Module (PCM) Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P0040 JEEP OBD Code Description At ignition on the Powertrain Control Module (PCM) checks the voltage on…