how to fix P0171 code on my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal.
• Allow the engine to cool completely before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Flashlight, vacuum gauge
• Carefully inspect all vacuum hoses for cracks or disconnections.
• Use a vacuum gauge to measure the vacuum at the intake manifold. If the reading is low, locate and repair any leaks.
• Replace any damaged hoses or gaskets as necessary.

3. Clean or Replace the MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Locate the MAF sensor on the air intake duct.
• Disconnect the electrical connector and remove the sensor from the duct.
• Spray the MAF sensor with MAF cleaner to remove any dirt and debris.
• Allow the sensor to dry completely before reinstalling it. If damaged, replace it with a new one.

4. Test and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel rail and connect the fuel pressure gauge to the service port.
• Turn the ignition to the "ON" position (do not start the engine) and check the fuel pressure reading.
• Compare this reading to the manufacturer's specifications. If low, inspect the fuel pump and filter for issues and replace as necessary.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaning kit or multimeter (for testing)
• If the fuel pressure is normal, remove the fuel injectors for inspection.
• Clean the injectors using a cleaning kit or replace them if they show signs of clogging or malfunction.
• Reinstall the injectors and ensure proper sealing.

6. Check the Engine Coolant Temperature Sensor

• Tools Required: Multimeter
• Locate the coolant temperature sensor and disconnect its electrical connector.
• Use a multimeter to check the resistance of the sensor and compare it to the specifications provided by the manufacturer.
• Replace the sensor if it is out of range or malfunctioning.