what does it mean if my Tesla Model 3 Highland (2024-present) has a P0420 code

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the vehicle to cool down if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor from the exhaust manifold using the O2 sensor socket.
• Install the new upstream oxygen sensor, ensuring it is tightened to the manufacturer's torque specifications.
• Repeat the process for the downstream oxygen sensor if it is also faulty.

3. Examine the Catalytic Converter

• Tools Required: Jack and jack stands, socket set
• Raise the vehicle on jack stands for access to the undercarriage.
• Inspect the catalytic converter for physical damage, such as dents, cracks, or signs of overheating.
• If damaged, remove the catalytic converter by unbolting it from the exhaust system.
• Install a new catalytic converter, ensuring to follow the manufacturer's installation instructions and torque specifications.

4. Check for Exhaust Leaks

• Inspect all exhaust connections and joints for leaks.
• Use exhaust sealant or replace gaskets as necessary to ensure a proper seal.

5. Reset the ECU

• Tools Required: OBD-II scanner
• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECU.