how to fix P0420 code in Ford Mustang S650 (2024-Present)

Solution

1. Preparation

• Tools Needed: OBD-II scanner, multimeter, infrared thermometer, socket set, jack stands, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Remove the oxygen sensor(s) by using a socket wrench to unscrew them from the exhaust system.
  2. Inspect the sensors for any signs of damage or contamination.
  3. If faulty, replace with new OEM sensors. Torque specifications typically range from 30-40 lb-ft.
  4. Reconnect the battery and clear the codes from the OBD-II scanner.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove the exhaust piping connected to the catalytic converter using a socket set.
  3. Inspect the catalytic converter for any signs of physical damage or clogging.
  4. If replacement is needed, install a new OEM catalytic converter in reverse order of removal, ensuring all bolts are torqued according to manufacturer specifications (usually around 30-35 lb-ft).
  5. Reconnect the exhaust system and lower the vehicle.

4. Final Checks

• Sub-steps:
  1. Reconnect the battery and clear all trouble codes.
  2. Start the engine and allow it to reach operating temperature.
  3. Monitor the vehicle's performance and check for any reappearance of the P0420 code after a short test drive.