how to fix P0420 code on Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to avoid electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor by using the O2 sensor socket.
  • Sub-steps:
    • Disconnect the electrical connector of the sensor.
    • Use the O2 sensor socket to unscrew the sensor from the exhaust manifold.
• Install the new upstream oxygen sensor, tightening to manufacturer specifications (typically around 30 Nm).
• Repeat the process for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter.
• Lift the vehicle securely using jack stands.
• Remove any heat shields covering the catalytic converter.
• Disconnect the exhaust pipes from the catalytic converter using a socket set.
  • Sub-steps:
    • Cut the exhaust pipes if they are too corroded or difficult to remove.
    • Remove bolts or clamps securing the catalytic converter.
• Install the new catalytic converter, ensuring a proper fit and seal.
• Reattach the exhaust pipes and any heat shields.

4. Reset the OBD-II System

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.