my Toyota RAV4 has a check engine light with P0138 code what should I check

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, multimeter, socket set, oxygen sensor socket, and safety gloves.
• Ensure the vehicle is parked on a flat surface and the engine is turned off.

2. Disconnect Battery

• Disconnect the negative terminal of the battery to eliminate electrical hazards.

3. Remove the Oxygen Sensor

• Locate the downstream oxygen sensor on the exhaust system.
• Use the oxygen sensor socket to carefully unscrew the sensor from its location.
• Inspect the sensor tip for excessive soot or damage.

4. Install New Oxygen Sensor

• Apply anti-seize compound to the threads of the new oxygen sensor (if not pre-applied).
• Thread the new sensor into the exhaust pipe and tighten it to the manufacturer’s torque specifications (typically around 30-40 lb-ft).

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0138 code from the engine control module.

6. Test Drive

• Start the engine and allow it to reach operating temperature.
• Monitor the check engine light to ensure it does not re-illuminate during a test drive.