P CODES (POWERTRAIN) P0100 - P0199 P0140

Definition of Trouble Code P0140 - Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

The trouble code P0140 indicates that the Powertrain Control Module (PCM) has detected a lack of activity or an irregular signal from the oxygen sensor located in Bank 1 Sensor 2. This oxygen sensor is placed after the catalytic converter and is responsible for monitoring the efficiency of the exhaust system. When the sensor fails to send the correct information to the PCM, it can cause poor engine performance, reduced fuel efficiency, and increased emissions.

Diagnosing Trouble Code P0140

Before you begin the diagnostic process, it's essential to have the appropriate tools and equipment. Here's a step-by-step guide on how to diagnose trouble code P0140:

1. First, you'll need an OBD-II scanner to read and clear the trouble codes. Connect the scanner to the OBD-II port under the dashboard, usually located on the driver's side. Turn on the ignition and retrieve the stored trouble codes. If P0140 is present, proceed to the next step.

2. Visually inspect the wiring and connectors related to Bank 1 Sensor 2 oxygen sensor for damage or corrosion. If there's visible damage, repair or replace the affected parts.

3. Check the voltage output of the oxygen sensor using a digital multimeter. The voltage should fluctuate between 0.1V and 0.9V when the engine is running at operating temperature. If the voltage remains constant or does not fluctuate, the sensor may be faulty.

4. Perform a resistance test on the oxygen sensor's heater circuit. Consult the vehicle's repair manual for the specific resistance value. If the resistance value is out of the specified range, replace the sensor.

Repairing Trouble Code P0140

Once you've diagnosed the issue, follow these steps to repair trouble code P0140:

1. If the wiring and connectors are damaged or corroded, repair or replace them as needed. Ensure all connections are secure and free of debris.

2. If the voltage output test indicates a faulty oxygen sensor, replace Bank 1 Sensor 2 oxygen sensor with a compatible one. Make sure to follow the manufacturer's guidelines and torque specifications.

3. If the resistance test on the heater circuit shows an out-of-range value, replace the oxygen sensor. Ensure the new sensor is compatible with your vehicle and follow the manufacturer's installation guidelines.

4. After completing the repairs, clear the trouble codes using the OBD-II scanner. Start the engine and let it reach operating temperature. Use the scanner to monitor the oxygen sensor's live data to ensure it's functioning correctly. If no issues are detected, take the vehicle for a test drive to confirm the repairs were successful.

Conclusion

Trouble code P0140 - Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 2) can be caused by a faulty oxygen sensor, damaged wiring, or corroded connectors. By following the step-by-step guide above, you can diagnose and repair the issue effectively. Remember always to consult your vehicle's repair manual for specific information and follow the manufacturer's guidelines to ensure a successful repair.