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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Raise the vehicle using jack stands for easier access to the exhaust components.

2. Inspect and Replace Oxygen Sensors

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

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter (if needed), gasket scraper.
• Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
• Inspect the catalytic converter for any blockage or damage. If it is clogged or damaged, replace it with a new unit.
• Clean the mating surfaces of the exhaust manifold and exhaust pipe.
• Install the new catalytic converter and torque the bolts to the manufacturer's specification (approximately 30 lb-ft).
• Replace any gaskets or seals if necessary.

4. Reconnect Battery and Clear Codes

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

5. Test Drive

• Conduct a test drive to allow the vehicle's computer to perform the necessary checks on the catalytic converter and oxygen sensors.