how to fix P0138 oxygen sensor error on Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent any electrical shorts.
• Ensure the vehicle is on a flat surface and properly supported if elevated.

2. Remove the Faulty O2 Sensor

• Locate the O2 sensor in the exhaust system (typically located upstream or downstream of the catalytic converter).
• Use a socket wrench with the appropriate O2 sensor socket to unscrew the sensor from its mounting.
• Carefully disconnect the wiring harness from the O2 sensor.

3. Inspect and Clean

• Inspect the O2 sensor port for carbon buildup or debris. Clean if necessary using a wire brush and throttle body cleaner.
• Check the connector for any signs of wear or corrosion. Clean the connector pins gently.

4. Install New O2 Sensor

• Install the new O2 sensor into the exhaust port, ensuring it is seated properly.
• Hand-tighten the sensor, then use a torque wrench to tighten it to the manufacturer’s specified torque (typically around 30-40 Nm).
• Reconnect the wiring harness to the new O2 sensor.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.
• Use the OBD-II scanner to check for any error codes after the engine has run.