how to fix the P0420 code in Tesla Model 3 Highland (2024-present)?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool down, especially if the exhaust system has been recently operated.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, ratchet.
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the sensor on the exhaust manifold or downpipe.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Inspect the sensor for damage or contamination.
  4. If damaged, replace with a new sensor, tightening to the manufacturer's specification (typically 30 Nm).
• Repeat the process for the downstream (post-catalytic) oxygen sensor.

3. Inspect and Clean or Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust clamp tool.
• Remove the catalytic converter:
  1. Disconnect the exhaust pipes from the catalytic converter using the appropriate socket.
  2. Remove any supporting brackets or heat shields if necessary.
  3. Inspect the catalytic converter for physical damage or clogging.
• If the converter is clogged or damaged, replace it with a new unit, ensuring to torque the bolts to manufacturer specifications.

4. Reconnect and Reset

• Reconnect all components:
  1. Reinstall the oxygen sensors and torque to specification.
  2. Reattach the exhaust pipe and secure it with clamps.
• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.