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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the vehicle to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove the upstream oxygen sensor: Use an oxygen sensor socket to unscrew and remove.
3. Install the new upstream oxygen sensor: Apply anti-seize compound on the threads (if not pre-coated) and torque to manufacturer specifications (usually around 30 lb-ft).
4. Remove the downstream oxygen sensor: Repeat the removal process for the downstream sensor.
5. Install the new downstream oxygen sensor: Follow the same installation procedure as the upstream sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Visual inspection: Check the catalytic converter for any signs of damage or blockage.
2. Remove the catalytic converter: Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe. Be cautious of exhaust hangers.
3. Install the new catalytic converter: Align it properly, then tighten bolts to the manufacturer’s torque specifications (usually around 30 lb-ft).
4. Reinstall exhaust hangers: Ensure all hangers are securely fastened.

4. Clear Error Codes

• Reconnect the negative terminal of the battery.
• Use an OBD-II scanner to clear any stored codes from the ECU.