Tesla Model S Plaid/Refresh (2021-present) P0420 code how to resolve

Learn how to diagnose and resolve P0420 code related to catalytic converter efficiency in Tesla Model S Plaid. Step-by-step guide included.

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, jack and jack stands, safety goggles, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal.

2. Inspect and Test Oxygen Sensors

• Locate the upstream and downstream oxygen sensors on the exhaust system.
• Using a multimeter, measure the voltage output of each sensor while the engine is idling.
  • Sub-step: For the upstream sensor, expect a fluctuating voltage between 0.1V and 0.9V.
  • Sub-step: For the downstream sensor, a stable voltage around 0.5V indicates proper function.
• If readings are outside these parameters, replace the faulty oxygen sensors.

3. Evaluate the Catalytic Converter

• Inspect the catalytic converter for any physical damage or signs of overheating (discoloration).
• Use a hammer to gently tap on the converter; listen for rattling, indicating internal damage.
• If the catalytic converter is damaged or clogged, it must be replaced.

4. Replace Components (if necessary)

• Oxygen Sensors Replacement:

  • Remove the sensor using an O2 sensor socket.
  • Install the new sensor and torque to manufacturer specifications (typically around 30 lb-ft).

• Catalytic Converter Replacement:

  • Disconnect any exhaust clamps and oxygen sensors attached to the catalytic converter.
  • Remove the bolts securing the catalytic converter to the exhaust manifold and exhaust pipe.
  • Install the new catalytic converter and ensure all connections are tight and leak-free.

5. Reset the Engine Control Unit (ECU)

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECU.
• Start the vehicle and allow it to reach operating temperature.