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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, exhaust pressure gauge.
• Ensure the vehicle is parked on a level surface and the engine is off. Allow the engine to cool completely before starting any work.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the Battery: Disconnect the negative battery terminal to ensure safety.
3. Remove the Sensors: Use a socket wrench to remove the oxygen sensors. Be cautious of the wiring harness.
4. Test the Sensors: Use a multimeter to check the resistance of the sensors and compare with OEM specifications.
5. Replace if Faulty: Install new oxygen sensors if the old ones are defective. Torque to manufacturer specifications.

3. Inspect and Replace the Catalytic Converter

1. Visual Inspection: Check for cracks, holes, or any signs of physical damage on the catalytic converter.
2. Remove the Old Catalytic Converter: Use a socket set to unbolt the catalytic converter from the exhaust system. Make sure to keep track of any gaskets or seals.
3. Install the New Catalytic Converter: Position the new catalytic converter and install it with new gaskets. Torque the bolts to manufacturer specifications.
4. Reattach the Exhaust System: Ensure all connections are tight and leak-free.

4. Final Checks

1. Reconnect the Battery: Reconnect the negative battery terminal.
2. Clear the Codes: Use the OBD-II scanner to clear the P0420 code.
3. Test Drive the Vehicle: Drive the vehicle for a short distance to ensure everything is functioning correctly and monitor for any reoccurrence of the error code.