how to fix Honda Civic 10th Generation (2016-2021) P0138 code

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before working on exhaust components.

2. Remove the Oxygen Sensor

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

3. Inspect and Clean

• Visually inspect the sensor threads for carbon buildup or damage.
• Clean the area around the sensor to prevent debris from entering the exhaust system during reinstallation.

4. Replace the Sensor

• Install the new oxygen sensor into the exhaust pipe, ensuring it is threaded correctly.
• Torque the sensor to the manufacturer’s specifications (typically around 30-40 lb-ft).
• Reconnect the electrical connector securely to the new sensor.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Use the OBD-II scanner to check if the P0138 code reappears.