Honda Pilot Third Generation (2016-present) P0420 code common fixes

Solution

1. Preparation

• Gather tools and materials required for the repair.
• Disconnect the battery to ensure safety while working on the vehicle.
• Raise the vehicle using jack stands for better access to the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Disconnect the electrical connectors from both sensors.
3. Using an oxygen sensor socket, remove the upstream sensor first, followed by the downstream sensor.
4. Install the new oxygen sensors in the reverse order, ensuring they are tightened to the manufacturer’s torque specification (usually around 30 lb-ft).
5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

1. If the catalytic converter is deemed faulty from the back pressure test, remove the exhaust pipe connected to the catalytic converter by loosening the bolts or clamps.
2. Carefully detach the catalytic converter from the exhaust manifold and the downstream pipe.
3. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
4. Reattach the exhaust pipe, tightening all bolts to the manufacturer’s specifications.
5. Use a new gasket if required to prevent exhaust leaks.

4. Clear Trouble Codes

1. Reconnect the vehicle's battery.
2. Use the OBD-II scanner to clear the P0420 trouble code from the vehicle's computer.
3. Start the engine and allow it to run for a few minutes to ensure proper operation.