Honda Accord 10th Generation (2018-2022) check engine light P0420 code what does it mean

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to reset the system.
• Allow the vehicle to cool down if recently used.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor:
  • Locate the sensor before the catalytic converter.
  • Use the O2 sensor socket to unscrew the sensor.
• Install the new upstream oxygen sensor:
  • Apply anti-seize compound to the threads of the new sensor.
  • Torque to manufacturer's specifications (typically around 33 lb-ft).
• Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, jack stands, torque wrench
• Raise the vehicle securely using jack stands.
• Remove the exhaust components as needed to access the catalytic converter.
• Inspect for damage; if required, unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
• Install the new catalytic converter:
  • Position it correctly and bolt it in place according to the manufacturer's torque specifications.
  • Ensure all gaskets are replaced to prevent leaks.

4. Reconnect Components

• Reconnect the battery.
• Reconnect any exhaust components that were removed, ensuring all connections are secure.

5. Clear Codes and Test Drive

• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and let it reach operating temperature.
• Perform a test drive to ensure the check engine light does not reappear.