how to fix P0420 code on Tesla Model 3 Original (2017-2023)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, OBD-II scanner.
• Sub-steps:
  1. Disconnect the negative battery terminal to prevent electrical shorts.
  2. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  3. Use the O2 sensor socket to remove the old sensors.
  4. Install new oxygen sensors (ensure they are compatible with the model).
  5. Reconnect the negative battery terminal.

3. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Sub-steps:
  1. Raise the vehicle safely using jack stands.
  2. Locate the catalytic converter and inspect for any obvious damage.
  3. Remove any heat shields or components obstructing access to the catalytic converter.
  4. Unbolt the catalytic converter from the exhaust system using the socket set.
  5. Install the new catalytic converter, ensuring proper alignment and sealing.
  6. Torque the bolts to the manufacturer’s specifications (typically around 25-30 ft-lbs, confirm with service manual).
  7. Reinstall any heat shields or components removed.

4. Clear Codes and Test

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code.
  2. Take the vehicle for a test drive to monitor performance and verify the absence of the check engine light.