DTC P0140 - Middle Oxygen Sensor Activity Not Detected: Condition

DTC is set when middle oxygen sensor signal voltage does not exceed .6 volt after engine is started, or stays below .6 volt for 98 seconds after engine has reached normal operating temperature. Engine speed at 1150 RPM or greater and voltage supplied to sensor heater. Possible causes are:

• Middle oxygen sensor.
• Open or short circuit between terminal No.3D on Powertrain Control Module (PCM) and terminal "A" (Yellow wire) on middle oxygen sensor.
• Open circuit between terminal No.3AB on Powertrain Control Module (PCM) and terminal "B" (Black/Blue wire) on middle oxygen sensor.
• Intake air system, fuel system and/or ignition system malfunction.