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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery cable to prevent electrical shorts.
• Allow the vehicle to cool down if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Inspect the sensor for damage or contamination; replace if necessary.
• Install the new upstream oxygen sensor and torque it to the manufacturer's specification (typically around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor if it is also faulty.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, penetrating oil
• Loosen and remove the exhaust bolts securing the catalytic converter to the exhaust system. Apply penetrating oil if bolts are rusted.
• Remove the catalytic converter from its mounting position.
• Inspect the new catalytic converter for any defects before installation.
• Install the new catalytic converter and torque the bolts to the manufacturer’s specifications (usually around 30 lb-ft).

4. Clear the Codes

• Reconnect the negative battery cable.
• Use the OBD-II scanner to clear any stored error codes from the vehicle's computer.

5. Test Drive

• Take the vehicle for a test drive to ensure that the check engine light remains off and the vehicle operates smoothly.