how to fix P0420 code in Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Inspect the sensors for damage or excessive carbon buildup.
• If damaged, replace them with new OEM sensors.
• Torque the new sensors to the manufacturer's specification (typically around 30-40 lb-ft).

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), exhaust sealant, torque wrench.
• Inspect the catalytic converter for physical damage or clogs.
• If replacement is needed, unbolt the catalytic converter from the exhaust system.
• If the converter is welded, carefully cut it out and prepare the exhaust for the new unit.
• Install the new catalytic converter, ensuring a proper fit and sealing the joints with exhaust sealant.
• Torque bolts to manufacturer's specifications.

4. Clear Codes and Test Drive

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0420 code and any other related codes.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive, ensuring to monitor for any reoccurrence of the P0420 code.