how to fix P0171 code on Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0171 engine lean condition in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, fuel pressure gauge, multimeter, socket set, torque wrench.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Intake Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or soapy water to identify leaks. If bubbles form, replace the affected hose or gasket.
  3. Tighten any loose clamps and ensure proper sealing of all connections.

3. Check and Clean the MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, typically found between the air filter and the throttle body.
  2. Remove the sensor using a socket set.
  3. Clean the MAF sensor with MAF cleaner spray. Allow it to dry completely before reinstallation.
  4. Reinstall the MAF sensor and ensure it is securely fastened.

4. Test Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail service port.
  2. Turn the ignition to the "ON" position without starting the engine to check the fuel pressure reading. It should be within the manufacturer's specifications (usually 55-65 psi).
  3. If the pressure is low, inspect the fuel pump and filter for issues and replace if necessary.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  1. Remove the engine cover to access the fuel injectors.
  2. Use a multimeter to check the resistance of each injector according to specifications (typically 12-16 ohms).
  3. If an injector is found to be faulty, replace it with a new one, ensuring the correct torque is applied during reinstallation.

6. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. If the oxygen sensors are identified as faulty during diagnostics, disconnect the battery again.
  2. Locate the upstream and downstream oxygen sensors on the exhaust system.
  3. Use a wrench to unscrew the faulty sensor and replace it with a new one.
  4. Reconnect the battery and ensure all connections are secure.