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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Disconnect the battery: To prevent electrical shorts, disconnect the negative terminal of the battery.
3. Remove the oxygen sensors:
   • Use a socket wrench with an O2 sensor socket to carefully unscrew the sensors from their positions.
   • Check the wiring for any signs of damage or corrosion.
4. Install new oxygen sensors:
   • Apply anti-seize compound on the threads of the new sensors.
   • Screw the new sensors into place and tighten to the manufacturer’s specifications (typically around 30 lb-ft).
5. Reconnect the battery.

3. Replace the Catalytic Converter (if necessary)

1. Lift the vehicle: Use a jack to lift the car and secure it with jack stands.
2. Remove exhaust components:
   • Disconnect the exhaust pipe from the catalytic converter by removing bolts with a socket set.
   • If applicable, remove any heat shields covering the catalytic converter.
3. Remove the old catalytic converter: Unscrew the bolts holding it in place and carefully remove it from the vehicle.
4. Install the new catalytic converter:
   • Position the new catalytic converter and secure it with bolts, tightening them to the manufacturer’s torque specifications.
   • Reattach the exhaust pipe and heat shields if removed.
5. Lower the vehicle.

4. Clear Codes and Test Drive

1. Clear the OBD-II codes: Use the scanner to clear the P0420 code.
2. Test drive the vehicle: Monitor for any reoccurrence of the check engine light and observe performance.