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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, exhaust gas temperature gauge, jack and jack stands.
• Disconnect the negative terminal of the battery to prevent electrical shock.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the pre-catalytic converter oxygen sensor (upstream) and the post-catalytic converter oxygen sensor (downstream).
  2. Disconnect the electrical connectors from both oxygen sensors.
  3. Use a socket wrench to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install new sensors, ensuring to apply anti-seize compound on the threads.
  5. Reconnect the electrical connectors.

3. Examine the Catalytic Converter

• Sub-steps:
  1. Inspect the catalytic converter for any signs of physical damage, such as dents or rust.
  2. If damaged, use a socket set to remove the catalytic converter from the exhaust system.
  3. Install a new catalytic converter, ensuring proper alignment and sealing.
  4. Torque all bolts to the manufacturer’s specifications.

4. Clear Error Codes

• Sub-steps:
  1. Reconnect the negative terminal of the battery.
  2. Use the OBD-II scanner to clear the P0420 error code from the system.
  3. Perform a test drive to allow the vehicle's systems to recalibrate.