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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Check the wiring and connectors of the upstream and downstream oxygen sensors for damage or corrosion.
• If the sensors are faulty, replace them:
  1. Remove the electrical connector.
  2. Use an O2 sensor socket to unscrew and remove the sensor.
  3. Install the new sensor and reconnect the electrical connector.

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

• Tools Required: Socket set, torque wrench, penetrating oil
• If the catalytic converter is found to be inefficient:
  1. Remove the exhaust heat shield (if equipped) by unbolting it.
  2. Disconnect the exhaust pipes from both ends of the catalytic converter.
  3. Remove the catalytic converter by unbolting it from the exhaust manifold and the exhaust pipe.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Torque the bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative terminal of the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.