my Ford Mustang S650 (2024-Present) has a check engine light with P0420 code, what to do?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, safety glasses, jack and jack stands, exhaust pipe cutter (if needed).
• Gather necessary replacement parts based on diagnosis.
• Safety Warnings: Disconnect the battery before working on electrical systems. Allow the exhaust system to cool before inspection.

2. Replace Oxygen Sensors (if faulty)

1. Locate the upstream and downstream oxygen sensors (usually positioned before and after the catalytic converter).
2. Disconnect the electrical connector from each oxygen sensor.
3. Use a socket to remove the faulty oxygen sensors from the exhaust system.
4. Apply anti-seize compound to the threads of the new sensors.
5. Install the new oxygen sensors and torque them to the manufacturer’s specifications.
6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. If the catalytic converter is determined to be faulty, ensure the vehicle is securely raised on jack stands.
2. Disconnect the exhaust pipes from both ends of the catalytic converter.
3. Use an exhaust pipe cutter if necessary to remove the old catalytic converter.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
5. Tighten all connections securely and torque to specifications.

4. Clear Codes and Test

1. Reconnect the battery and use the OBD-II scanner to clear the check engine light codes.
2. Perform a test drive to ensure the check engine light does not reappear and monitor for any symptoms.