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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and raise it using jack stands if necessary.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the sensor on the exhaust manifold.
  2. Use the O2 sensor socket to unscrew the sensor from the exhaust.
  3. Install the new sensor, tightening it to the manufacturer’s specified torque.
• Repeat for the downstream (post-catalytic) oxygen sensor if needed.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torch, exhaust clamp tool.
• Remove the catalytic converter:
  1. Loosen and remove the bolts/clamps securing the catalytic converter to the exhaust system.
  2. Carefully remove the catalytic converter from the exhaust system.
• Install the new catalytic converter:
  1. Position the new converter in place, ensuring proper alignment with the exhaust.
  2. Secure it using new gaskets and tighten all bolts/clamps to the specified torque.

4. Reset the Engine Control Module (ECM)

• Reconnect the battery.
• Using the OBD-II scanner, clear the P0420 code from the ECM.
• Start the engine and allow it to reach operating temperature.