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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and secured with wheel chocks.
• Disconnect the negative terminal of the battery to avoid electrical issues.

2. Replace Faulty Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Instructions:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Use the O2 sensor socket to remove the faulty sensors.
  3. Install new oxygen sensors and torque them to manufacturer specifications (usually around 30 lb-ft).
  4. Reconnect the electrical connectors for each sensor.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket (if needed)
• Instructions:
  1. Remove the exhaust heat shield if applicable.
  2. Unbolt the catalytic converter from the exhaust pipe and the exhaust manifold.
  3. Inspect the catalytic converter for any physical damage or blockage.
  4. Install the new catalytic converter, ensuring proper alignment. Use a new exhaust gasket if required.
  5. Torque the bolts to the manufacturer's specifications (usually around 25 lb-ft).

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner
• Instructions:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.
  3. Perform a test drive to allow the ECM to re-evaluate the system.