how to fix P0420 code in Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, oxygen sensor removal tool.
• Safety Warnings: Disconnect the battery before beginning any electrical work. Allow the engine to cool before working on exhaust components.

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system, focusing on connections and joints.
  2. Tighten any loose bolts or clamps.
  3. Replace any damaged gaskets or components found during inspection.

3. Test and Replace Oxygen Sensors

• Sub-steps:
  1. Using a multimeter, check the voltage output of the upstream oxygen sensor while the engine is running (should fluctuate between 0.1V and 0.9V).
  2. If the readings are outside this range, replace the upstream oxygen sensor.
  3. Repeat the voltage test on the downstream oxygen sensor (should remain relatively stable).
  4. Replace the downstream oxygen sensor if it shows abnormal readings or if the P0420 persists after replacing the upstream sensor.

4. Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust pipe bolts securing the catalytic converter using a socket set.
  2. Carefully lower the catalytic converter from its mounting position.
  3. Install the new catalytic converter, ensuring all gaskets are properly seated.
  4. Torque the exhaust pipe bolts to the manufacturer's specifications as per the service manual.

5. Clear Codes and Test

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and allow it to reach operating temperature, then take the vehicle for a test drive to monitor if the code reappears.