what does it mean when my Tesla Outback shows a P0171 code?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a flat surface and safely secured.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect leaks while monitoring engine RPMs.
  3. Replace any damaged hoses or gaskets as necessary.

3. Clean the Mass Air Flow Sensor

• Sub-steps:
  1. Locate the MAF sensor, usually found between the air filter and the throttle body.
  2. Carefully disconnect the electrical connector.
  3. Remove the MAF sensor using the appropriate socket.
  4. Spray MAF cleaner on the sensor element; do not touch it.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail's service port.
  2. Turn the ignition to the "ON" position without starting the engine to check the pressure.
  3. Compare the reading to the manufacturer's specifications; it should generally be around 50-60 psi.
  4. If pressure is low, check the fuel pump and filter for issues; replace if needed.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail according to the vehicle's service manual.
  2. Inspect each injector for clogs or leaks.
  3. Clean injectors using a proper cleaning kit or replace them if they are faulty.

6. Verify Throttle Body Function

• Sub-steps:
  1. Remove the air intake duct to access the throttle body.
  2. Inspect for carbon buildup and clean with throttle body cleaner if necessary.
  3. Ensure the throttle plate opens and closes smoothly without sticking.