how to fix the P0174 code on my Toyota Corolla E170 (2013-2019)

Learn how to diagnose and fix P0174 lean condition in Toyota Corolla E170 (2013-2019). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Air Intake System

1. Visual Inspection: Examine all air intake hoses and connections for cracks or looseness.
   • Tools Required: Screwdriver set, flashlight.
2. Replace Damaged Hoses: If any hoses are damaged, replace them with OEM parts.
   • Parts Required: Replacement hoses as necessary.

3. Clean or Replace MAF Sensor

1. Remove MAF Sensor: Disconnect the electrical connector and unscrew the MAF sensor from the air intake duct.
   • Tools Required: Torx screwdriver.
2. Clean MAF Sensor: Use MAF sensor cleaner spray to clean the sensor element. Allow it to dry completely before reinstallation.
   • Safety Warnings: Ensure the cleaner is non-residue leaving.
3. Reinstall MAF Sensor: Secure it back in place and reconnect the electrical connector.

4. Check Fuel Pressure

1. Install Fuel Pressure Gauge: Connect the gauge to the fuel rail service port.
   • Tools Required: Fuel pressure gauge.
2. Check Pressure: Turn the ignition to the "ON" position (do not start the engine) and check the fuel pressure against the specifications (typically 43-50 psi for this model).
3. Replace Fuel Pump if Necessary: If the pressure is below specifications, replace the fuel pump.

5. Inspect and Clean Fuel Injectors

1. Remove Injectors: Disconnect the fuel rail and remove the injectors from the engine.
   • Tools Required: Socket set.
2. Clean Injectors: Soak the injectors in a cleaning solution or use an ultrasonic cleaner.
3. Reinstall or Replace: If injectors are clogged beyond cleaning, replace them with new ones.