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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical short circuits.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Remove the upstream oxygen sensor using the O2 sensor socket.
  • Sub-steps:
    1. Disconnect the electrical connector from the sensor.
    2. Using the O2 sensor socket, unscrew the sensor from the exhaust manifold.
    3. Install the new upstream oxygen sensor and reconnect the electrical connector.
• Repeat for the downstream oxygen sensor if testing shows it is faulty.

3. Check and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter if necessary.
• Inspect the catalytic converter visually for any signs of physical damage or blockage.
• If replacement is necessary, remove the damaged catalytic converter:
  • Sub-steps:
    1. Disconnect any exhaust pipes or sensors connected to the catalytic converter.
    2. Remove mounting bolts using a socket set.
    3. If required, use an exhaust pipe cutter to remove the old catalytic converter.
    4. Install the new catalytic converter, ensuring proper alignment and secure mounting.
    5. Torque the bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals securely.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.