what does it mean if my Tesla Model 3 Highland (2024-present) shows code P0420?

Solution

1. Preparation

• Gather required tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Disconnect the battery to prevent electrical shock.
  2. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  3. Using the O2 sensor socket, carefully remove the upstream O2 sensor.
  4. Install the new upstream O2 sensor, tightening to the manufacturer's specified torque (typically around 30 lb-ft).
  5. Repeat the process for the downstream O2 sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust gasket, torque wrench.
• Sub-steps:
  1. Safely lift the vehicle using a jack and secure it with jack stands.
  2. Remove the exhaust pipes connected to the catalytic converter using the socket set.
  3. Unbolt and remove the old catalytic converter carefully, ensuring no damage to surrounding components.
  4. Clean the mounting surfaces and install a new catalytic converter with a new exhaust gasket.
  5. Reconnect the exhaust pipes and tighten all bolts to the manufacturer's specifications.

4. Reconnect Battery and Reset Codes

• Tools Required: None.
• Sub-steps:
  1. Reconnect the battery terminals, ensuring they are secure.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s memory.