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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Remove the sensor connectors carefully.
  3. Use a socket wrench to unscrew the oxygen sensors.
  4. Inspect the sensors for any signs of damage or contamination.
• Tools Required: Oxygen sensor socket, multimeter.

3. Replace Defective Oxygen Sensors (if necessary)

• Sub-steps:
  1. Install new oxygen sensors in their respective locations.
  2. Torque the sensors to the manufacturer's specifications (usually around 30-40 lb-ft).
  3. Reconnect the sensor connectors ensuring a secure fit.
• Tools Required: Torque wrench.

4. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust piping connected to the catalytic converter.
  2. Unbolt the catalytic converter from the vehicle, noting any gaskets or sealing materials.
  3. Install a new catalytic converter using new gaskets to prevent leaks.
  4. Reattach the exhaust piping and tighten all bolts to manufacturer specifications.
• Tools Required: Socket set, gasket scraper.

5. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use an OBD-II scanner to clear the P0420 code.
  3. Start the vehicle and perform a test drive to ensure the check engine light remains off.
• Tools Required: OBD-II scanner.