my Tesla Model 3 Highland (2024-present) has a P0420 code, what does that mean?

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and ensure the engine is cool.
• Disconnect the 12V battery to ensure safety.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Apply penetrating oil to the sensor threads if they are rusted.
  3. Use the O2 sensor socket and ratchet to unscrew the sensors.
  4. Install the new oxygen sensors, tightening to the manufacturer's specified torque (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, cutting tools (if necessary for exhaust), gaskets.
• Sub-steps:
  1. Remove any exhaust clamps and bolts securing the catalytic converter.
  2. If needed, cut the exhaust pipe using appropriate cutting tools to remove the catalytic converter.
  3. Install the new catalytic converter, ensuring proper alignment.
  4. Reattach any bolts and clamps, tightening them to the specified torque.
  5. Replace exhaust gaskets as necessary to prevent leaks.

4. Reconnect Battery and Clear Codes

• Reconnect the 12V battery.
• Use the OBD-II scanner to clear any stored trouble codes.