how to troubleshoot my Tesla Model 3 Original (2017-2023) with a P0420 error code

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety goggles, gloves.
• Ensure that the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Use a socket set to remove the sensors carefully.
3. Inspect the sensors for damage or contamination; replace if necessary.
4. Install new sensors, tightening to manufacturer specifications (typically 30-40 Nm).
5. Reconnect the battery.

3. Check and Replace Catalytic Converter

1. Safely lift the vehicle using a jack and secure with jack stands.
2. Remove the exhaust heat shield if present, using a socket set.
3. Disconnect the exhaust pipes from the catalytic converter by removing the bolts.
4. Inspect the catalytic converter for any internal damage or clogging; replace if necessary.
5. Install the new catalytic converter, ensuring proper alignment and sealing.
6. Reattach the exhaust heat shield and lower the vehicle.

4. Clear Error Codes

1. Reconnect the OBD-II scanner to the vehicle.
2. Clear the P0420 error code from the system.
3. Start the engine and allow it to reach operating temperature.