how to fix P0171 code on Toyota RAV4 Fourth Generation (2013-2018)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers
• Remove the air filter housing and inspect the air filter for dirt or blockages. Replace if necessary.
• Check all intake hoses and connections for cracks or loose fittings. Replace any damaged hoses.
• Inspect the intake manifold gasket for any leaks. Replace if necessary.

3. Check and Clean Mass Airflow Sensor (MAF)

• Tools Required: MAF cleaner or isopropyl alcohol, soft cloth
• Locate the MAF sensor in the air intake path.
• Carefully detach the electrical connector.
• Remove the MAF sensor from its housing.
• Clean the sensor with MAF cleaner or isopropyl alcohol. Allow it to dry completely.
• Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel pressure test port on the fuel rail.
• Connect the fuel pressure gauge to the port and turn the ignition to the "ON" position without starting the engine.
• Check the pressure reading against manufacturer specifications (typically around 30-40 psi). If low, inspect the fuel pump and filter for issues.

5. Inspect and Test Fuel Injectors

• Tools Required: Fuel injector cleaner, multimeter (for electrical testing)
• Remove the fuel rail to access the injectors.
• Inspect injectors for clogs or leaks. Clean or replace as necessary.
• Use a multimeter to check the resistance of the injectors. Compare with specifications to ensure proper operation.

6. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner
• Use a smoke machine to check for vacuum leaks around gaskets and hoses. If unavailable, spray carburetor cleaner near suspected areas and listen for RPM changes.
• Repair any identified leaks.