how to fix P0420 code on Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shorts.
• Allow the engine to cool completely before beginning work.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Remove the sensors: Use an oxygen sensor socket to unscrew the sensors from their mounting locations.
3. Inspect the connectors: Check the wiring and connectors for any signs of damage or corrosion.
4. Install new sensors: Apply anti-seize compound on the threads of the new sensors and install them securely, ensuring not to over-tighten. Torque values should be according to the manufacturer’s specifications.
5. Reconnect the battery: Reconnect the vehicle's battery after all installation is complete.

3. Inspect and Replace the Catalytic Converter

1. Remove exhaust components: If necessary, remove any exhaust pipes or brackets that obstruct access to the catalytic converter using a socket set.
2. Inspect the catalytic converter: Check for physical damage or signs of clogging (e.g., excessive heat discoloration).
3. Install a new catalytic converter: Position the new converter in place, ensuring the gasket is properly seated to prevent leaks.
4. Secure the converter: Use the appropriate fasteners and torque to specifications to attach the catalytic converter to the exhaust system.
5. Reassemble exhaust components: Reattach any removed pipes or brackets, ensuring all connections are tight.