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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, OBD-II scanner
• Locate and remove the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Inspect the connectors and wiring for damage; replace if necessary.
• Install new oxygen sensors, ensuring proper torque (typically around 30 lb-ft) as specified by the manufacturer.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed), new gaskets
• Remove any bolts securing the catalytic converter to the exhaust pipe and the exhaust manifold.
• Carefully detach the catalytic converter from the exhaust system.
• Install the new catalytic converter, ensuring that all gaskets are replaced and the installation is secure.
• Torque all bolts to the manufacturer's specifications.

4. Reset the Engine Control Module (ECM)

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