how to fix the P0420 code on a Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle battery.
• Allow the vehicle to cool down before beginning any work on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench, multimeter
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Use the O2 sensor socket to remove the upstream sensor. Inspect the sensor for wear or damage.
  3. If the sensor is faulty, install a new oxygen sensor, tightening it to the manufacturer's specifications (typically around 30-40 ft-lbs).
  4. Repeat the process for the downstream sensor if necessary.

3. Examine and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, gasket scraper
• Sub-steps:
  1. Remove any bolts securing the catalytic converter to the exhaust pipes using the socket set.
  2. Use the exhaust hanger removal tool to detach the catalytic converter from its hangers.
  3. Inspect the old catalytic converter for internal damage or blockage.
  4. Clean the mating surfaces on the exhaust pipes with a gasket scraper.
  5. Install the new catalytic converter and secure it with bolts, tightening them to the manufacturer's torque specifications (usually around 30-40 ft-lbs).
  6. Reattach any exhaust hangers that were removed.

4. Reconnect Battery and Test

• Reconnect the vehicle battery.
• Start the engine and allow it to idle for a few minutes.
• Monitor the engine performance and check for any warning lights.