DTC P0140 - Rear Oxygen Sensor Activity Not Detected: Condition

DTC is set when rear oxygen sensor signal voltage does not exceed .55 volt after engine is started, or stays below .55 volt for 80 seconds after engine has reached normal operating temperature. Engine speed at 1500 RPM or greater and voltage supplied to sensor heater. Possible causes are:

• Low fuel level.
• Rear oxygen sensor.
• Open or short circuit between terminal No. 2K on Engine Control Module (ECM) and terminal "A" (Red/Blue wire) on rear oxygen sensor.
• Open circuit between terminal No. 3O on Engine Control Module (ECM) and terminal "B" (Brown/Yellow wire) on rear oxygen sensor.
• Intake air system, fuel system and/or ignition system malfunction.