how to fix the P0420 code on my Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the exhaust system to cool before proceeding.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor:
  • Disconnect the electrical connector.
  • Use the O2 sensor socket to remove the sensor from the exhaust manifold.
• Install the new upstream oxygen sensor:
  • Apply anti-seize compound on the threads (if not pre-coated).
  • Thread the sensor by hand to avoid cross-threading, then tighten to the manufacturer's specified torque (usually around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor if necessary.

3. Test the Catalytic Converter

• Tools Required: Infrared thermometer
• Use the infrared thermometer to measure the inlet and outlet temperatures of the catalytic converter.
  • Inlet temperature: Measure at the front of the catalytic converter.
  • Outlet temperature: Measure at the rear of the catalytic converter.
• Compare the temperatures; a significant difference (usually 100°F or more) indicates proper catalytic converter function. If no significant difference is observed, consider replacing the catalytic converter.

4. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter
• Disconnect the exhaust pipes from the catalytic converter:
  • Use the socket set to unbolt the exhaust flanges.
  • Cut any necessary hangers or clamps.
• Remove the old catalytic converter and install the new one:
  • Position the new catalytic converter and secure it with the provided gaskets and bolts.
  • Tighten to the manufacturer's specified torque.
• Reconnect the exhaust system and hangers.

5. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Test drive the vehicle for at least 20 minutes to ensure the code does not reappear.