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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the battery to avoid any electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, anti-seize compound.
• Remove the pre-catalytic converter oxygen sensor:
  1. Locate the pre-cat O2 sensor (usually before the catalytic converter).
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Apply anti-seize compound to the threads of the new sensor.
  4. Install the new sensor and torque it to the manufacturer's specifications.
• Repeat for the post-catalytic converter oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust sealant, and gaskets if required.
• Remove the catalytic converter:
  1. Unscrew the bolts securing the catalytic converter to the exhaust system.
  2. If applicable, detach any hangers or clamps holding the converter in place.
  3. Carefully remove the catalytic converter from the vehicle.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Secure it to the exhaust system using the original or new bolts.
  3. Ensure all gaskets are replaced, and use exhaust sealant if necessary.
  4. Torque all bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.