my Honda Accord Eleventh Generation (2023-present) engine light is on and I got a P0420 code, what d...

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and extension
• Remove the upstream (pre-catalytic converter) oxygen sensor:
  1. Locate the sensor on the exhaust manifold.
  2. Use the O2 sensor socket and ratchet to unscrew the sensor.
  3. Disconnect the wiring harness from the sensor.
• Install the new oxygen sensor:
  1. Apply anti-seize compound on the threads of the new sensor.
  2. Connect the wiring harness and screw in the sensor securely.
  3. Torque to manufacturer specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, and exhaust gasket
• Remove the catalytic converter:
  1. Disconnect the exhaust pipes from the catalytic converter by removing the bolts.
  2. If necessary, remove any heat shields or brackets securing the converter.
  3. Carefully detach the catalytic converter from the exhaust system.
• Install a new catalytic converter:
  1. Position the new converter and align it with the exhaust pipes.
  2. Install and torque the bolts to manufacturer specifications (typically 25-30 ft-lbs).
  3. Replace any gaskets as needed to prevent leaks.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and let it run until it reaches operating temperature.
• Test drive the vehicle to ensure the check engine light does not return.