how to fix P0420 code on Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Find the pre-catalytic and post-catalytic oxygen sensors.
2. Unplug the connectors: Carefully disconnect the electrical connectors from both oxygen sensors.
3. Remove sensors: Use an oxygen sensor socket to remove both sensors from the exhaust system.
4. Inspect sensor condition: Check for any signs of damage or contamination.
5. Install new sensors: Apply anti-seize compound to the threads of the new sensors and install them in reverse order of removal.
6. Reconnect electrical connectors: Ensure they are securely connected.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Visual inspection: Check for physical damage or blockage in the catalytic converter.
2. Remove exhaust components: If replacement is needed, loosen and remove bolts securing the catalytic converter to the exhaust system.
3. Remove old catalytic converter: Carefully detach the catalytic converter from the exhaust system.
4. Install new catalytic converter: Position the new converter and secure it with new gaskets and bolts.
5. Torque bolts: Use a torque wrench to tighten bolts to manufacturer specifications (typically around 30-40 lb-ft for exhaust components).

4. Reset Engine Control Module (ECM)

1. Reconnect the battery: Reconnect the negative battery terminal.
2. Clear codes: Use the OBD-II scanner to clear any trouble codes from the engine control module.