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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, exhaust pipe cutter (if necessary).
• Disconnect the battery before beginning any repairs.
• Allow the engine to cool down completely to avoid burns.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust pipes.
  4. If necessary, test the sensors with a multimeter to ensure they are functioning properly (check for voltage and resistance).
  5. Install new oxygen sensors by screwing them into place and tightening to the manufacturer’s torque specifications (typically around 30 ft-lbs).
  6. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. If the oxygen sensors are functioning correctly, inspect the catalytic converter for any signs of physical damage or clogs.
  2. If damage is found, use an exhaust pipe cutter to remove the defective catalytic converter.
  3. Install the new catalytic converter, ensuring proper orientation.
  4. Tighten all bolts to the manufacturer’s torque specifications (usually around 20-30 ft-lbs).
  5. Reattach any heat shields or brackets that were removed.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 error code from the vehicle’s computer.
  3. Start the engine and let it idle for a few minutes to ensure proper function.