how to fix P0420 code in Honda Pilot YF4 (2023-Present) if the catalytic converter was replaced?

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Raise the vehicle safely using jack stands if necessary.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter, socket set.
• Remove the oxygen sensor from the exhaust before the catalytic converter.
• Use a multimeter to test the sensor’s voltage output while the engine is running; it should fluctuate between 0.1V to 0.9V.
• If the sensor is faulty, replace it with a new one.

3. Check Exhaust Leaks

• Visually inspect the exhaust system for cracks or holes, particularly around the joints and seams.
• If leaks are found, replace the damaged components (e.g., gaskets, pipes) and ensure all connections are tight.

4. Verify Catalytic Converter Installation

• Ensure that the new catalytic converter is the correct model for the Honda Pilot YF4.
• Check that all mounting brackets are secure and that there are no exhaust leaks around the flanges.
• Reinstall or replace any hardware that may be damaged or missing.

5. Reset the Engine Control Module (ECM)

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.
• Start the vehicle and allow it to reach operating temperature.