what causes P0420 code on my Ford Mustang S650 (2024-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to prevent electrical shorts.
• Allow the exhaust system to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Install the new upstream oxygen sensor and torque to manufacturer specifications (typically around 30 ft-lbs).
• Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, cutting tools (if welding is required), jack stands, safety glasses.
• Raise the vehicle securely on jack stands.
• Remove the bolts securing the catalytic converter to the exhaust system using the socket set.
• If the converter is welded in place, use cutting tools to carefully remove it.
• Install the new catalytic converter and secure with bolts. Torque to manufacturer specifications.
• If welding, ensure proper welding techniques are employed for a secure fit.

4. Reset the Engine Control Module (ECM)

• Reconnect the vehicle battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.