how to fix P0420 code in Honda Accord 8th Generation (2008-2012)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.
• Disconnect the battery to ensure safety while working on the electrical components.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Lift the vehicle using a jack and secure it with jack stands.
  2. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  3. Disconnect the electrical connectors from both oxygen sensors.
  4. Use a socket wrench to remove the oxygen sensors from the exhaust manifold and catalytic converter.
  5. Install new oxygen sensors, ensuring they are properly torqued (generally around 30 lb-ft).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Inspect the catalytic converter for signs of physical damage or obstruction.
  2. If replacement is necessary, use a socket set to remove the mounting bolts securing the catalytic converter.
  3. Carefully detach the catalytic converter from the exhaust system.
  4. Install the new catalytic converter, ensuring proper alignment and using new gaskets if required.
  5. Torque the bolts to the manufacturer's specifications (typically around 25 lb-ft).

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use the OBD-II scanner to clear the P0420 code from the engine control module.