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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Oxygen Sensors

• Sub-steps:
  • Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  • Unplug the electrical connectors from both sensors.
  • Use a multimeter to check the resistance and voltage output of each sensor according to the manufacturer specifications.
  • Replace any faulty oxygen sensors as needed.

3. Examine and Replace Catalytic Converter

• Sub-steps:
  • Raise the vehicle safely using jack stands.
  • Remove the exhaust heat shields if applicable.
  • Unbolt the catalytic converter from the exhaust system using a socket set.
  • Inspect the catalytic converter for any physical damage or blockage.
  • Install the new catalytic converter, ensuring proper alignment.
  • Torque the bolts to the manufacturer's specified torque values.

4. Reconnect and Clear Codes

• Sub-steps:
  • Reconnect the oxygen sensors and ensure all electrical connections are secure.
  • Reconnect the negative battery terminal.
  • Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.

5. Test the System

• Sub-steps:
  • Start the engine and allow it to reach operating temperature.
  • Perform a test drive while monitoring for any reoccurrence of the check engine light.
  • Use the OBD-II scanner again to verify that no new codes have appeared.