Honda Pilot YF4 (2023-Present) how to fix check engine light P0420

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and securely set with wheel chocks.
• Disconnect the battery to prevent electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Locate the upstream and downstream oxygen sensors (usually found on the exhaust manifold and after the catalytic converter).
• Use an O2 sensor socket or wrench to carefully unscrew the sensors from their respective locations.
• Install the new oxygen sensors by threading them in hand-tight, then torque to the manufacturer's specifications (usually around 30 ft-lbs).
• Reconnect the electrical connectors to the new sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• If the catalytic converter is damaged or inefficient, it may need to be replaced.
• Remove the exhaust pipes connected to the catalytic converter using a socket set, taking care not to damage surrounding components.
• Support the catalytic converter with a jack or hoist.
• Remove the old catalytic converter and install the new one, ensuring that the gaskets are properly aligned.
• Reattach the exhaust pipes and torque the nuts/bolts to the specified values.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals and ensure they are secure.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Start the engine and allow it to reach operating temperature.