how to fix P0420 code on Honda CR-V Sixth Generation (2023-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down completely before starting the repair.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Remove the oxygen sensor connectors.
• Use the multimeter to check the voltage output of the pre-catalytic (upstream) sensor and post-catalytic (downstream) sensor.
  • Upstream should fluctuate between 0.1 to 0.9 volts.
  • Downstream should be relatively stable if the catalytic converter is functioning.

3. Examine the Catalytic Converter

• Tools Required: Socket set, torque wrench.
• Inspect the catalytic converter for any visible damage or rattling noise, indicating internal failure.
• If damage is found, proceed to replace the catalytic converter.

4. Replace the Catalytic Converter

• Tools Required: Exhaust flange gasket, new catalytic converter, socket set, torque wrench.
• Remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
• Replace with a new converter, ensuring the exhaust flange gasket is in good condition.
• Torque the bolts to the manufacturer’s specifications (typically around 30-40 lb-ft).

5. Reconnect Oxygen Sensors

• Reattach the oxygen sensors to their respective connectors.
• Ensure that the wiring is secure and not exposed to heat or moving parts.

6. Reconnect Battery and Clear Codes

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