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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts or shocks.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Step 1: Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Step 2: Disconnect the electrical connectors from the sensors.
• Step 3: Use an O2 sensor socket and ratchet to remove the sensors from the exhaust system.
• Step 4: Install the new oxygen sensors, ensuring to apply anti-seize compound on the threads if recommended.
• Step 5: Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Step 1: Remove the exhaust heat shield if applicable, using a socket set.
• Step 2: Disconnect the exhaust pipe from the catalytic converter by removing the bolts or clamps.
• Step 3: Remove the catalytic converter from the vehicle.
• Step 4: Install the new catalytic converter, ensuring it is properly aligned and secured.
• Step 5: Reconnect the exhaust pipe and reattach the heat shield.

4. Reconnect Battery and Clear Codes

• Step 1: Reconnect the negative battery terminal.
• Step 2: Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Step 3: Start the engine and let it idle for a few minutes to ensure everything is functioning correctly.