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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is in a safe, well-ventilated area.
• Disconnect the 12V battery to prevent electrical shorts while working on the sensors.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Remove the upstream oxygen sensor by using the O2 sensor socket and ratchet.
  2. Install the new upstream oxygen sensor and torque to manufacturer specifications (typically around 30 Nm).
  3. Repeat the process for the downstream oxygen sensor if it is also faulty.

3. Inspect Exhaust System

• Tools Required: Socket set, flashlight
• Sub-steps:
  1. Visually inspect the entire exhaust system for cracks, holes, or loose connections.
  2. Tighten any loose bolts or connections found during inspection.
  3. If any damage is evident, replace the affected exhaust components.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, exhaust hanger removal tool, torque wrench
• Sub-steps:
  1. Remove the bolts securing the catalytic converter to the exhaust system.
  2. Carefully detach the catalytic converter from its mountings, using the exhaust hanger removal tool if necessary.
  3. Install the new catalytic converter and secure it with bolts, torquing to the manufacturer's specifications (consult service manual for exact values).
  4. Reconnect any electrical connections or sensors.

5. Reconnect Battery

• Reconnect the 12V battery and ensure all connections are tight.