how to fix Honda Pilot YF3 (2016-2022) P0420 check engine light code

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands, safety goggles, gloves.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket to remove the upstream oxygen sensor.
3. Inspect the sensor for damage; replace if necessary.
4. Repeat for the downstream oxygen sensor.
5. Install the new oxygen sensors and torque to manufacturer specifications (usually around 30 Nm).
6. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

1. If the catalytic converter is damaged or the temperature test failed, it may need replacement.
2. Raise the vehicle using a jack and secure it with jack stands.
3. Remove the bolts securing the catalytic converter to the exhaust pipes using a socket set.
4. Carefully lower the catalytic converter and inspect for internal damage or blockage.
5. Install the new catalytic converter, ensuring proper alignment and sealing.
6. Torque the bolts to the manufacturer's specifications (refer to service manual, typically around 40 Nm).

4. Clear Codes and Test Drive

1. Use the OBD-II scanner to clear the P0420 code from the ECU.
2. Start the vehicle and let it warm up.
3. Take the vehicle for a test drive to ensure the check engine light does not reappear and monitor for performance issues.