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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
• Using an O2 sensor socket, carefully unscrew the faulty sensors.
• Apply anti-seize compound to the threads of the new sensors.
• Install the new sensors and torque them to the manufacturer's specification (typically around 30 lb-ft).
• Reconnect the wiring harnesses.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Jack and jack stands, socket set, exhaust clamps, gasket material
• Support the vehicle using jack stands for safety.
• Disconnect the exhaust pipes from the catalytic converter using a socket set. Remove any clamps.
• Inspect the old catalytic converter for damage or clogs.
• If replacement is needed, install the new catalytic converter with new gaskets to prevent leaks.
• Reattach the exhaust pipes and secure them with clamps, ensuring a tight fit.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and let it idle for a few minutes.
• Take the vehicle for a test drive under various conditions to ensure the check engine light does not reappear.