how do I fix the P0420 code on my Honda Pilot Third Generation (2016-present)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Park the vehicle on a flat 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, ratchet, torque wrench.
• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Disconnect the electrical connectors from both sensors.
• Use the O2 sensor socket to unscrew the sensors from the exhaust manifold and catalytic converter respectively.
• Install new oxygen sensors by screwing them into place and tightening them to the manufacturer's specifications (typically around 30 lb-ft).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust hangers removal tool.
• Raise the vehicle using a jack and secure it with jack stands.
• Inspect the catalytic converter for physical damage or blockage.
• If replacement is necessary, unbolt the catalytic converter from the exhaust system using the socket set.
• Remove any exhaust hangers with the hangers removal tool.
• Install the new catalytic converter, ensuring that gaskets are in good condition and properly aligned.
• Torque the bolts to manufacturer's specifications (typically around 30-45 lb-ft).

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to ensure that the check engine light does not reappear.