how to fix P0420 code on Tesla Model S Original (2012-2020)

Learn how to diagnose and fix P0420 exhaust system issue in Tesla Model S. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool to prevent burns.

2. Inspect and Replace O2 Sensors (if defective)

• Tools Required: Oxygen sensor socket, ratchet and extension
• Remove the upstream oxygen sensor (sensor before the catalytic converter) by:
  1. Unplugging the electrical connector.
  2. Using the oxygen sensor socket to unscrew the sensor.
• Install the new oxygen sensor:
  1. Apply anti-seize compound to the threads (if not pre-applied).
  2. Screw in the new sensor and tighten to the manufacturer’s specification (typically 30-40 lb-ft).
  3. Reconnect the electrical connector.
• Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter (if defective)

• Tools Required: Socket set, torque wrench, exhaust gasket
• Remove the catalytic converter by:
  1. Loosening and removing the bolts at the exhaust manifold and the exhaust pipe.
  2. Carefully removing the catalytic converter from its mounts.
• Inspect the old catalytic converter for signs of damage or blockage.
• Install the new catalytic converter:
  1. Position the new catalytic converter and align it with the exhaust system.
  2. Install new bolts or re-use old ones if in good condition, tightening to the specified torque (typically 30-35 lb-ft).
  3. Replace any necessary gaskets to prevent leaks.

4. Final Checks

• Reconnect the battery terminal.
• Clear the error codes using an OBD-II scanner.
• Start the engine and allow it to reach operating temperature. Check for leaks and ensure the check engine light does not reappear.