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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use a socket wrench to disconnect the wiring harness from each sensor.
  3. Remove the oxygen sensors using a wrench.
  4. Install new oxygen sensors and reconnect the wiring harness.
• Tools Required: Oxygen sensor socket, socket wrench, torque wrench.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Remove any heat shields or covers obstructing access to the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust system using a socket wrench.
  3. Inspect the catalytic converter for damage and blockage.
  4. Install a new catalytic converter, ensuring proper alignment.
  5. Torque bolts to the manufacturer’s specifications (typically around 30-40 lb-ft).
• Tools Required: Socket set, torque wrench, pry bar.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 error code.
  3. Perform a short test drive to ensure the check engine light does not return.
• Tools Required: OBD-II scanner.