how to fix P0420 code in my Tesla Model 3 Highland (2024-present)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Locate Oxygen Sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Remove Sensors: Use an oxygen sensor socket to carefully remove both sensors.
3. Test Sensors: Using a multimeter, check the voltage output of the oxygen sensors. If readings are outside the normal range, replace the faulty sensor.
4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors and install them, tightening to the manufacturer's specified torque (typically around 30 lb-ft).

3. Inspect and Repair Exhaust System

1. Check for Leaks: Visually inspect the exhaust system for any cracks or leaks, particularly near the catalytic converter.
2. Repair or Replace Components: Use exhaust sealant or clamps to repair minor leaks. For major damage, replace the affected exhaust section.

4. Replace the Catalytic Converter (if necessary)

1. Remove the Old Converter: Unbolt the catalytic converter from the exhaust system using a socket set. Be careful to support the exhaust system to prevent damage.
2. Inspect Mounting Flanges: Check flanges for damage or warping. Replace gaskets as necessary.
3. Install New Converter: Position the new catalytic converter and secure it with bolts, ensuring proper alignment.
4. Torque Bolts: Tighten the bolts to the specified torque (usually around 25 lb-ft).

5. Reconnect Battery and Clear Codes

1. Reconnect Battery: Once all repairs are completed, reconnect the vehicle's battery.
2. Clear Codes: Use the OBD-II scanner to clear the P0420 code from the system.