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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety during the repair process.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use a wrench to remove both sensors from the exhaust system.
  4. Install new oxygen sensors and torque them to the manufacturer's specifications.
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove any heat shields if applicable.
  3. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  4. Remove the catalytic converter from the mounting brackets.
  5. Install the new catalytic converter, ensuring proper alignment with the exhaust pipes.
  6. Torque all bolts to the specified values.
  7. Reinstall any heat shields removed earlier.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Test drive the vehicle under various conditions to ensure the code does not reappear.