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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Raise the vehicle and secure it on jack stands, ensuring it is stable.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Remove the upstream (pre-catalytic) oxygen sensor using a socket wrench.
• Connect the multimeter to the sensor's terminals and check the voltage output. It should fluctuate between 0.1V and 0.9V.
• Replace the oxygen sensor if it is out of range or faulty.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Locate the catalytic converter and inspect it for physical damage or blockage.
• If damaged, unbolt the catalytic converter from the exhaust system using a socket set.
• Remove any exhaust gaskets and clean the mating surfaces.
• Install the new catalytic converter with a new gasket, ensuring it is properly aligned.
• Torque the bolts to the manufacturer’s specifications.

4. Reinstall Oxygen Sensors

• Reinstall the upstream oxygen sensor after the catalytic converter is replaced.
• If applicable, install the downstream (post-catalytic) oxygen sensor as well.
• Ensure all connections are secure and free from contaminants.

5. Reset the Engine Control Module (ECM)

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.
• Start the vehicle and allow it to run for a few minutes to ensure no new codes appear.