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

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 battery to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Inspect the upstream and downstream oxygen sensors for damage or corrosion.
• If faulty, remove the sensors using the O2 sensor socket.
  1. Use the ratchet to loosen and remove the oxygen sensors from the exhaust manifold and catalytic converter.
  2. Install new oxygen sensors, tightening them to the manufacturer's specifications (typically around 30 lb-ft).

3. Check and Replace Catalytic Converter (if necessary)

• Parts Required: New catalytic converter (if defective)
• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if applicable), gasket sealant
• If the catalytic converter is confirmed defective, proceed with replacement:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove any bolts securing the catalytic converter to the exhaust system using a socket set.
  3. If necessary, use an exhaust pipe cutter to remove the old catalytic converter.
  4. Clean the mating surfaces on the exhaust pipes.
  5. Install the new catalytic converter and secure it using the bolts, applying gasket sealant if required.
  6. Torque the bolts to the manufacturer's specifications (typically around 40-50 lb-ft).

4. Reconnect Battery and Clear Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the stored codes from the vehicle's computer.