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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, exhaust gas temperature probe.
• Gather replacement parts if necessary, such as oxygen sensors or a catalytic converter.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

1. Remove the Negative Battery Terminal:
   • Use a wrench to disconnect the negative terminal to prevent electrical shorts.
2. Locate the Oxygen Sensors:
   • Identify the upstream and downstream oxygen sensors on the exhaust system.
3. Remove the Sensors:
   • Use a socket or wrench to unscrew the sensors from their respective locations.
4. Test Sensors:
   • Use a multimeter to check each sensor's resistance and voltage output against manufacturer specifications.
5. Install New Sensors (if needed):
   • Apply anti-seize compound to the threads of new sensors and install them, tightening to manufacturer specifications.

3. Inspect and Replace Catalytic Converter

1. Remove Exhaust Components:
   • Unbolt any necessary exhaust components to access the catalytic converter.
   • Use a torque wrench to ensure proper reinstallation.
2. Check for Damage:
   • Inspect the catalytic converter for physical damage or clogging.
3. Replace Catalytic Converter (if necessary):
   • Remove the old catalytic converter and install a new one, ensuring proper alignment and sealing.
   • Use new gaskets where applicable to prevent exhaust leaks.

4. Clear Codes and Test

1. Reconnect Battery Terminal:
   • Reconnect the negative battery terminal and ensure all connections are secure.
2. Clear OBD-II Codes:
   • Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Conduct a Test Drive:
   • Drive the vehicle to allow the engine to reach operating temperature and monitor for any reoccurrence of the code.