how to diagnose the P0420 catalyst efficiency code in Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, exhaust leak detection tool, safety goggles, gloves
• Safety Warnings: Ensure the vehicle is parked on a flat surface, and the engine is cool before beginning any inspection.

2. Inspect and Replace O2 Sensors (if faulty)

1. Disconnect Battery: Remove the negative terminal to ensure safety while working on electrical components.
2. Locate O2 Sensors: Identify the upstream and downstream O2 sensors on the exhaust system.
3. Remove Sensors: Use an O2 sensor socket to unscrew and remove the faulty sensors.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors and install them securely.
5. Reconnect Battery: Reattach the negative battery terminal.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Lift Vehicle: Use a jack and jack stands to safely lift the vehicle for better access to the exhaust system.
2. Remove Exhaust Components: Disconnect exhaust pipes leading to and from the catalytic converter using a socket set.
3. Inspect Catalytic Converter: Check for physical damage or blockage in the converter; replace if necessary.
4. Install New Catalytic Converter: Position the new converter and reconnect the exhaust pipes, ensuring all connections are tight.
5. Lower Vehicle: Safely lower the vehicle back to the ground.

4. Clear Codes and Test Drive

1. Clear Codes: Use the OBD-II scanner to clear any diagnostic trouble codes.
2. Test Drive: Drive the vehicle for a short distance to monitor performance and check for reoccurrence of the P0420 code.