why does my Tesla Model 3 Highland (2024-present) have a check engine light for code P0420

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to avoid electrical shorts.
• Safely lift the vehicle using jack stands.

2. Inspect and Remove the Catalytic Converter

• Locate the catalytic converter under the vehicle.
• Remove any heat shields or covers if applicable.
• Unbolt the catalytic converter from the exhaust system using a socket set.
• Carefully lower the catalytic converter and inspect for internal blockage or damage.

3. Replace Faulty Components

• If the catalytic converter is found to be defective, replace it with a new unit that meets OEM specifications.
• If oxygen sensors are faulty, replace the upstream (pre-catalytic) and/or downstream (post-catalytic) sensors.
  • Tools Required: Oxygen sensor socket, torque wrench, penetrating oil (if bolts are stuck).

4. Reassemble the Exhaust System

• Reinstall the catalytic converter and tighten the bolts to the manufacturer's torque specifications.
• Reattach any heat shields or covers.
• Ensure all fasteners are secure and there are no exhaust leaks.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.