how to fix P0420 code on Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Remove the negative battery terminal.
• Locate the pre-catalytic and post-catalytic oxygen sensors.
• Use the O2 sensor socket to unscrew and remove the sensors.
• Inspect the sensors for any signs of damage.
• Install new oxygen sensors, ensuring they are properly threaded and tightened to manufacturer specifications (usually around 30 lb-ft).

3. Replace the Catalytic Converter (if required)

• Tools Required: Socket set, torque wrench, exhaust gasket
• Remove any heat shields or covers obstructing access to the catalytic converter.
• Disconnect the exhaust pipes from the catalytic converter using a socket set.
• Remove the old catalytic converter and inspect the exhaust gaskets.
• Install the new catalytic converter, ensuring it is oriented correctly.
• Reattach the exhaust pipes and tighten all connections to manufacturer torque specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and any other stored codes.
• Start the vehicle and allow it to reach operating temperature.