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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge
• Inspect the air intake ducting for cracks or loose connections.
• Tighten any loose clamps or replace damaged hoses.
• Use a vacuum gauge to check for any vacuum leaks; address any found leaks by replacing faulty components.

3. Clean Mass Air Flow (MAF) Sensor

• Tools Required: MAF sensor cleaner
• Remove the air intake duct to access the MAF sensor.
• Carefully detach the MAF sensor from its housing.
• Spray MAF sensor cleaner onto the sensor elements; do not touch them.
• Allow it to dry completely before reassembling.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel pressure test port on the fuel rail.
• Connect the fuel pressure gauge and turn the ignition key to the "ON" position without starting the engine.
• Check if the fuel pressure is within the manufacturer’s specifications (typically between 30-50 PSI for RAV4).
• If pressure is low, inspect the fuel pump and filter for issues.

5. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit (if needed), socket set
• If the fuel pressure is adequate, remove the fuel injectors for inspection.
• Use a fuel injector cleaning kit to flush out deposits; alternatively, replace with new injectors if they are faulty.

6. Test Oxygen Sensor

• Tools Required: Multimeter
• Disconnect the upstream oxygen sensor.
• Use a multimeter to test voltage output; it should fluctuate between 0.1 and 0.9 volts.
• Replace the sensor if it does not meet specifications.