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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Locate the pre-catalytic converter (upstream) oxygen sensor and the post-catalytic converter (downstream) oxygen sensor.
• Remove the connectors by pressing the release tab and pulling them off.
• Using the O2 sensor socket, unscrew the sensors and replace them with new ones. Torque to the manufacturer's specifications (usually around 30 lb-ft).
• Reconnect the sensor connectors ensuring they click securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Locate the catalytic converter in the exhaust system.
• Use the exhaust hanger removal tool to detach the exhaust hangers if necessary.
• Unscrew the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe using the socket set.
• Remove the old catalytic converter and install the new one, ensuring proper alignment.
• Torque the bolts to the manufacturer's specifications and reattach the exhaust hangers.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive under varied conditions (city and highway) to ensure proper function and monitor for any reoccurrence of the code.