how to fix P0420 code on Honda Pilot Third Generation (2016-present)?

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative battery terminal to prevent electrical short circuits.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Remove the old O2 sensor located before the catalytic converter (upstream).
• Install the new O2 sensor, ensuring that it is properly threaded and secured. Torque to manufacturer specifications (usually around 30 ft-lbs).
• Repeat the process for the downstream O2 sensor if necessary.

3. Catalytic Converter Inspection

• Tools Required: Jack and jack stands, exhaust pipe cutter, socket set
• Raise the vehicle and securely support it with jack stands.
• Inspect the catalytic converter for physical damage or blockage.
• If damage is found, use an exhaust pipe cutter to remove the old catalytic converter.
• Install a new catalytic converter, ensuring proper alignment and securing with exhaust clamps. Torque bolts to specifications.

4. Clear Codes and Reconnect Battery

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.

5. Test Drive

• Drive the vehicle for a minimum of 20-30 minutes to allow the engine control module (ECM) to re-evaluate the catalytic converter efficiency and confirm the repair.