my Tesla Model 3 Original (2017-2023) has a P0420 code, what does it mean?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal for safety.

2. Inspect and Replace Oxygen Sensors

• Remove the upstream and downstream oxygen sensors using an O2 sensor socket.
• Inspect the sensors for signs of damage or contamination.
• If faulty, replace with new OEM oxygen sensors.
• Reconnect the sensors and ensure they are secured properly.

3. Inspect and Replace the Catalytic Converter

• Raise the vehicle securely on jack stands.
• Remove any heat shields covering the catalytic converter (if applicable).
• Unbolt the catalytic converter from the exhaust system using a socket set.
• Inspect the catalytic converter for signs of failure, such as rattling or discoloration.
• If necessary, replace the catalytic converter with an OEM part, ensuring proper alignment and sealing.
• Torque the bolts to the manufacturer’s specifications (typically around 25-30 lb-ft, but confirm with service manual).

4. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the ECM.