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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface, engage the parking brake, and turn off the ignition.
• Disconnect the vehicle battery to ensure safety during repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream (pre-catalytic converter) oxygen sensor:
  1. Locate the upstream O2 sensor on the exhaust manifold.
  2. Use an O2 sensor socket to unscrew the sensor.
  3. Install the new O2 sensor and torque to manufacturer's specifications (usually around 30 Nm).
• Repeat for the downstream (post-catalytic converter) oxygen sensor if it is faulty.

3. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if applicable)
• Remove the catalytic converter:
  1. Locate the catalytic converter and inspect the mounting bolts.
  2. If the bolts are rusted, apply penetrating oil and allow it to sit.
  3. Unbolt the converter from the exhaust system, noting the orientation for installation.
  4. If necessary, cut the exhaust pipes with an exhaust cutter.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place, ensuring proper alignment.
  2. Bolt the converter to the exhaust system, tightening to the manufacturer’s torque specifications.

4. Reconnect Battery and Clear Codes

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