how to fix P0171 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and materials.
• 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, vacuum gauge
• Visually inspect all air intake hoses for cracks or loose connections.
• Use a vacuum gauge to check for leaks in the intake manifold.
• Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, screwdriver
• Remove the MAF sensor from the air intake duct.
• Spray the MAF sensor with MAF cleaner and allow it to dry completely.
• Reinstall the MAF sensor and ensure all connections are secure.

4. Test and Repair Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Attach the fuel pressure gauge to the fuel rail and turn the ignition to the "On" position (without starting the engine).
• Check if the fuel pressure is within manufacturer specifications (typically 40-50 psi).
• If pressure is low, inspect and replace the fuel pump or fuel filter as necessary.

5. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaner kit, socket set
• Remove the fuel injectors from the engine.
• Use a fuel injector cleaning kit to clean the injectors.
• Reinstall the injectors ensuring proper sealing and connections.

6. Check and Replace Oxygen Sensor (if necessary)

• Tools Required: O2 sensor socket, torque wrench
• Locate the upstream oxygen sensor and disconnect the wiring harness.
• Remove the sensor using an O2 sensor socket.
• Install the new oxygen sensor, tightening it to the manufacturer's torque specifications (usually around 30 lb-ft).
• Reconnect the wiring harness.