how to resolve the P0171 code issue in my Toyota Corolla E170 (2013-2019)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal of the battery to avoid electrical shorts.
• Allow the engine to cool before starting any work.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, vacuum gauge.
• Inspect the air intake hoses for cracks or disconnections.
• Use a vacuum gauge to check for vacuum leaks.
• Replace any damaged hoses or components as necessary.

3. Clean or Replace Mass Airflow Sensor (MAF)

• Tools Required: Torx screwdriver, MAF cleaner.
• Disconnect the MAF sensor's electrical connector.
• Remove the MAF sensor from the air intake tube.
• Clean the MAF sensor with MAF cleaner, ensuring not to touch the sensor elements.
• Reinstall the MAF sensor and reconnect the electrical connector. If the MAF is faulty, replace it.

4. Check and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position without starting the engine to check the pressure.
• If the pressure is out of specifications, inspect the fuel pump and filter for issues. Replace as necessary.

5. Inspect and Clean Fuel Injectors

• Tools Required: Injector cleaning kit.
• Remove the fuel injectors from the fuel rail.
• Use an injector cleaning kit to clean or replace clogged injectors.
• Reinstall the injectors ensuring proper sealing.

6. Check Engine Coolant Temperature (ECT) Sensor

• Tools Required: Multimeter.
• Disconnect the ECT sensor connector.
• Use a multimeter to check the resistance of the ECT sensor at various temperatures.
• Replace the ECT sensor if it is outside the specified range.