how to fix P0420 code on my Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors

• Inspect the Oxygen Sensors:
  • Remove the upstream and downstream oxygen sensors using an O2 sensor socket.
  • Inspect the connectors and wiring for damage.
• Replace the Oxygen Sensors:
  • Install new upstream and downstream oxygen sensors (if faulty).
  • Torque the oxygen sensors to manufacturer specifications (usually around 30 ft-lbs).
  • Reconnect the connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Remove the Catalytic Converter:
  • Loosen and remove the bolts securing the catalytic converter to the exhaust system using a socket set.
  • Carefully remove the catalytic converter from the vehicle.
• Install New Catalytic Converter:
  • Position the new catalytic converter in place.
  • Torque the bolts to manufacturer specifications (usually around 30 ft-lbs).
  • Ensure gaskets are replaced if necessary to prevent exhaust leaks.

4. Reset ECU

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECU.