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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use an O2 sensor socket to remove the faulty sensor(s).
  3. Install new oxygen sensors, ensuring they are properly torqued (refer to service manual for specific torque values).
  4. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  4. Remove the catalytic converter from the exhaust system.
  5. Install the new catalytic converter, ensuring proper alignment and secure it with the appropriate hardware.
  6. Reinstall any heat shields or brackets.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 error code.
  3. Start the engine and allow it to run for a few minutes to check for any reoccurring codes.