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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the vehicle's high-voltage battery for safety.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Remove the connectors from the upstream and downstream oxygen sensors.
• Using the O2 sensor socket, unscrew the faulty oxygen sensors from the exhaust system.
• Install new oxygen sensors in the reverse order, ensuring they are torqued to manufacturer specifications (typically around 30-40 lb-ft).
• Reconnect the connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Remove the exhaust hangers using the exhaust hanger removal tool to gain access to the catalytic converter.
• Unscrew the bolts securing the catalytic converter to the exhaust system using the socket set.
• Carefully remove the catalytic converter from the vehicle.
• Install the new catalytic converter, ensuring that it is aligned properly and securely tightened to the manufacturer’s torque specifications.
• Reattach exhaust hangers.

4. Reconnect Battery and Reset Codes

• Reconnect the vehicle's high-voltage battery.
• Use an OBD-II scanner to clear the P0420 code and any other stored codes.
• Start the vehicle and allow it to reach operating temperature.