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

Solution

1. Preparation

• Tools Required: OBD-II scanner, infrared thermometer, basic hand tools (socket set, wrenches), multimeter
• Ensure the vehicle is parked on a level surface and the parking brake is engaged. Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace the Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream and downstream oxygen sensors on the exhaust system.
2. Remove the Sensors: Use a socket or wrench to carefully unscrew the sensors from their locations.
3. Inspect the Sensors: Check for signs of damage, contamination, or carbon buildup.
4. Replace if Necessary: If the sensors are faulty, install new O2 sensors by screwing them into place and tightening to manufacturer specifications.

3. Inspect the Catalytic Converter

1. Visual Inspection: Look for any signs of damage, such as dents, rust, or disconnections in the exhaust system.
2. Temperature Test: Use an infrared thermometer to measure the inlet and outlet temperatures of the catalytic converter. The outlet should be significantly hotter than the inlet (usually around 100°F higher).
3. Replace if Faulty: If the catalytic converter shows signs of failure, remove it from the exhaust system, unbolt it from the flanges, and replace it with a new unit following manufacturer specifications.

4. Reset the Engine Control Module

1. Reconnect the Battery: After repairs, reconnect the battery terminals securely.
2. Clear the Error Codes: Use the OBD-II scanner to clear the P0420 code from the ECM.
3. Test Drive: Drive the vehicle to allow the ECM to relearn and monitor for the P0420 code to reappear.