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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to ensure safety.
• Allow the vehicle to cool down to prevent burns.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor:
  1. Locate the upstream oxygen sensor (typically before the catalytic converter).
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Compare the old sensor with the new one to ensure compatibility.
  4. Install the new sensor, torque to manufacturer specifications (typically around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor (located after the catalytic converter).

3. Inspect/Replace Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter, welding equipment (if necessary)
• Inspect the catalytic converter for damage:
  1. Check for physical damage or signs of overheating.
  2. If damaged, cut out the old catalytic converter using the exhaust pipe cutter.
  3. Install the new catalytic converter, ensuring proper alignment.
  4. Use welding equipment to secure the new component if required.
• Ensure all exhaust connections are tight to prevent leaks.

4. Clear Codes and Test

• Tools Required: OBD-II scanner
• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the error codes.
• Start the vehicle and let it run for a few minutes.
• Check for any reoccurring codes.