how to fix P0420 code on Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect Oxygen Sensors

• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Use a socket wrench to disconnect the oxygen sensor connectors.
• Test each sensor’s voltage output with a multimeter while the engine is running:
  • Expected voltage for the upstream sensor: 0.1V to 0.9V fluctuating.
  • Expected voltage for the downstream sensor: should be relatively stable around 0.5V.
• Replace any faulty oxygen sensors.

3. Inspect and Test the Catalytic Converter

• If oxygen sensors are functional, check the catalytic converter:
  • Remove any heat shields if applicable.
  • Use an infrared thermometer to measure inlet and outlet temperatures.
  • The temperature difference should be around 100°F (38°C) or more; if not, the catalytic converter may be faulty.
• If the catalytic converter is defective, proceed to replace it.

4. Replace the Catalytic Converter (if necessary)

• Remove the catalytic converter from the exhaust system:
  • Use a socket set to remove mounting bolts and clamps.
  • Carefully detach the catalytic converter from the exhaust pipe.
• Install the new catalytic converter:
  • Ensure gaskets are in place and secure the new converter with bolts to the exhaust system.
  • Torque bolts to the manufacturer's specifications (typically around 40-50 ft-lbs).
• Reattach any heat shields removed earlier.

5. Reconnect Battery and Clear Codes

• Reconnect the vehicle battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.