how to fix P0171 lean code in my Tesla Outback 5th Generation (2015-2019)

Solution

1. Preparation

• Gather necessary tools and parts. Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative terminal of the battery to avoid any electrical issues while working.

2. Inspect and Repair Vacuum Leaks

• Inspect all vacuum hoses and connections around the intake manifold.
• Replace any damaged hoses or gaskets.
• Use a smoke test if necessary to locate hard-to-find leaks.

3. Clean or Replace MAF Sensor

• Remove the MAF sensor from the air intake duct.
• Use MAF cleaner spray to clean the sensor element; do not touch the sensor with fingers or tools.
• Reinstall the MAF sensor and ensure it is secured.

4. Check Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail's Schrader valve.
• Turn the ignition on (without starting the engine) and check the pressure reading. It should match the manufacturer's specifications (typically between 50-60 psi).
• If the pressure is low, consider replacing the fuel pump or checking the fuel filter for clogs.

5. Inspect and Test Fuel Injectors

• Remove the fuel injectors from the fuel rail.
• Use a multimeter to check the resistance of each injector. Refer to manufacturer specifications for acceptable values.
• If any injectors are faulty, replace them with new units.

6. Test and Replace Oxygen Sensors (if necessary)

• Use a multimeter to test the voltage and response time of the upstream oxygen sensor.
• If the sensor is slow to respond or shows constant voltage, replace it with a new sensor.