how to fix P0420 code in Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather tools and necessary parts for the repair.
• Tools Required:
  • OBD-II scanner
  • Multimeter
  • Infrared thermometer
  • Socket set
  • Torque wrench
• Safety Warnings:
  • Disconnect the battery before working on electrical systems.
  • Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Disconnect the battery.
  2. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors on the exhaust system.
  3. Remove the electrical connectors and unscrew the sensors using a socket wrench.
  4. Install the new oxygen sensors and reconnect the electrical connectors.
  5. Torque the sensors to the manufacturer's specifications.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Raise the vehicle securely using jack stands.
  2. Locate the catalytic converter in the exhaust system.
  3. Inspect for physical damage, clogging, or excessive carbon buildup.
  4. If replacement is needed, unbolt the old catalytic converter using a socket set.
  5. Remove the old gasket and clean the mating surfaces.
  6. Install the new catalytic converter with a new gasket, ensuring proper alignment.
  7. Torque the bolts to the manufacturer's specifications.

4. Reset the Engine Control Module (ECM)

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.