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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, exhaust backpressure gauge, safety goggles, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical issues.

2. Inspect and Test Oxygen Sensors

• Sub-steps:
  • Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  • Using the multimeter, measure the voltage output of each sensor while the engine is running. The upstream sensor should fluctuate between 0.1 to 0.9 volts, while the downstream sensor should be relatively stable.
  • If any sensor is faulty, replace it with a compatible part.

3. Inspect Exhaust System

• Sub-steps:
  • Visually inspect the exhaust manifold, pipes, and catalytic converter for any cracks, corrosion, or loose connections.
  • Repair or replace any damaged components as necessary.

4. Backpressure Test on Catalytic Converter

• Sub-steps:
  • Use an exhaust backpressure gauge to check for excessive backpressure in the exhaust system.
  • If backpressure exceeds the manufacturer's specifications, replace the catalytic converter.

5. Replace Catalytic Converter (if necessary)

• Sub-steps:
  • Remove the bolts securing the catalytic converter to the exhaust system using a socket set.
  • Carefully detach the catalytic converter from its mounting points.
  • Install the new catalytic converter, ensuring proper alignment and sealing.
  • Torque the bolts to the manufacturer's specifications.

6. Reconnect Battery and Clear Codes

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