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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench.

2. Inspect and Replace Oxygen Sensors

• Locate the upstream and downstream oxygen sensors.
  • Use the socket set to remove the sensors from the exhaust system.
• Test the sensors.
  • Connect the multimeter to the sensor terminals and check for proper voltage readings (usually between 0.1V to 0.9V for switching sensors).
• Replace any faulty sensors.
  • Install new sensors and torque to manufacturer specifications (typically around 30 Nm).

3. Inspect and Replace Catalytic Converter

• Assess the catalytic converter's condition.
  • Look for signs of damage, excessive carbon build-up, or rattling noises.
• Remove the catalytic converter.
  • Disconnect the exhaust pipes leading to the catalytic converter and unbolt it using the socket set.
• Install the new catalytic converter.
  • Position the new unit and secure it with bolts, torquing to manufacturer specifications.
• Reconnect exhaust system components ensuring all gaskets are properly seated.

4. Reset the Engine Control Unit (ECU)

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECU.
• Test drive the vehicle for at least 20 minutes to allow the ECU to re-learn the parameters.