how to fix the P0420 code on my Tesla Model 3 Original (2017-2023)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety glasses, gloves.
• Safety Warnings: Disconnect the battery before working on electrical systems. Allow the exhaust system to cool before inspection.

2. Inspect and Repair Exhaust System

• Sub-steps:
  • Lift the vehicle using a jack and secure it with jack stands.
  • Inspect the entire exhaust system for leaks, cracks, or loose connections. Pay special attention to joints and welds.
  • If a leak is found, replace damaged sections of exhaust piping or tighten loose connections.

3. Test and Replace Oxygen Sensors

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors.
  • Disconnect the electrical connectors from the sensors.
  • Using a multimeter, test the output voltage of the sensors while the engine is running (typically, the voltage should oscillate between 0.1V and 0.9V for a functioning sensor).
  • If any sensor is faulty, remove it using a sensor socket and replace it with a new one. Torque the new sensor to manufacturer specifications (usually around 30 lb-ft).

4. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  • If the catalytic converter is found to be clogged or damaged during inspection, remove the old catalytic converter by unbolting it from the exhaust system.
  • Install a new catalytic converter, ensuring all gaskets are replaced and connections are secure.
  • Torque bolts to manufacturer specifications (typically around 25-35 lb-ft).

5. Clear Codes and Test Drive

• Sub-steps:
  • Reconnect the battery.
  • Use the OBD-II scanner to clear the P0420 code.
  • Test drive the vehicle to ensure the code does not return and the vehicle performs correctly.