my Honda Accord has a check engine light with code P0138, what should I do?

Learn how to diagnose and fix P0138 high voltage from the oxygen sensor in Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before proceeding.

2. Remove the Oxygen Sensor

• Locate the upstream oxygen sensor (usually near the engine or exhaust manifold).
• Use an oxygen sensor socket or wrench to unscrew the sensor from the exhaust pipe.
• Disconnect the electrical connector from the oxygen sensor.

3. Inspect and Clean

• Examine the oxygen sensor for signs of damage or contamination.
• Check the wiring harness for frays or corrosion.
• Clean the sensor threads and the area around the sensor mount on the exhaust pipe.

4. Install New Oxygen Sensor

• If the old sensor is faulty, install a new oxygen sensor in the reverse order of removal.
• Ensure the sensor is tightened to the manufacturer’s specifications (typically 30-40 ft-lbs).
• Reconnect the electrical connector securely.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Monitor the engine for any signs of issues or reactivation of the check engine light.