how to fix Tesla Model 3 Highland (2024-present) P0420 code for catalyst issue

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety goggles, gloves.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors on the exhaust system.
2. Use a socket wrench to remove the oxygen sensors from their respective positions.
3. Inspect the sensors for damage or contamination.
4. If faulty, install new oxygen sensors, ensuring they are tightened to the manufacturer's torque specifications (typically around 30 Nm or 22 ft-lbs).
5. Reconnect the electrical connectors to the sensors.

3. Examine and Replace the Catalytic Converter (if necessary)

1. Inspect the catalytic converter for physical damage or signs of clogging.
2. If replacement is necessary, use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
3. Carefully detach the catalytic converter from the exhaust pipes, ensuring no exhaust gases leak during the process.
4. Install the new catalytic converter, tightening bolts to the manufacturer's specifications.
5. Ensure all gaskets and seals are replaced to prevent exhaust leaks.

4. Reconnect Battery and Test

1. Reconnect the negative battery terminal.
2. Start the vehicle and allow it to reach operating temperature.
3. Use the OBD-II scanner to clear the P0420 code and any other related codes.
4. Take the vehicle for a test drive to monitor performance and check for the reappearance of the check engine light.