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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, jack and jack stands.
• Ensure the vehicle is parked on a level surface. Disconnect the battery to prevent electrical shorts during repairs.

2. Inspect Exhaust System

• Sub-steps:
  1. Raise the vehicle using jack stands for access to the underside.
  2. Visually inspect the exhaust system from the engine to the tailpipe for leaks or damage.
  3. Tighten any loose connections or replace damaged sections as necessary.

3. Test and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the sensor connectors and remove them using a socket wrench.
  3. Use a multimeter to test the voltage output of the sensors. Replace if readings are out of specification.
  4. Install the new sensors and reconnect the electrical connectors.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. If the catalytic converter is damaged or clogged, remove it by unbolting it from the exhaust system.
  2. Install a new catalytic converter, ensuring proper alignment with exhaust pipes.
  3. Torque bolts to manufacturer specifications (typically around 30-50 ft-lbs, check service manual).
  4. Reconnect any sensors or components removed during installation.