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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Exhaust pipe cutter (if needed)

2. Inspect Oxygen Sensors

• Locate the upstream and downstream oxygen sensors.
• Disconnect the electrical connectors from both sensors.
• Use a multimeter to test the sensors:
  • For the upstream sensor, check for voltage output while the engine is running.
  • For the downstream sensor, verify that the voltage fluctuates as expected.
• Replace any faulty sensors with new ones.

3. Inspect and Replace Catalytic Converter

• If the catalytic converter shows signs of physical damage or inefficiency:
  • Remove any associated heat shields.
  • Use the socket set to unbolt the catalytic converter from the exhaust system.
  • Install the new catalytic converter by reversing the removal process.
  • Ensure all bolts are torqued to manufacturer specifications.

4. Reconnect and Reset

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.