how to address the P0138 code in my Toyota RAV4 XA40 (2013-2018)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down if it has been running.

2. Remove the Upstream Oxygen Sensor

• Locate the upstream O2 sensor on the exhaust manifold.
• Use a wrench to carefully unscrew the sensor from its mounting point.
• Disconnect the electrical connector attached to the sensor.

3. Inspect and Replace

• Inspect the old O2 sensor for any signs of damage, such as corrosion or physical wear.
• If the sensor is faulty, install the new O2 sensor:
  • Apply anti-seize compound to the threads of the new sensor (if not pre-applied).
  • Hand-tighten the sensor into the exhaust manifold and then use a torque wrench to tighten it to the manufacturer's specifications (usually around 30-40 ft-lbs).
• Reconnect the electrical connector securely.

4. Reconnect Battery and Perform Reset

• Reconnect the negative battery terminal.
• Clear any stored codes using the OBD-II scanner.
• Start the engine and let it idle for a few minutes.