how to fix P0174 code in Toyota Corolla E170 (2013-2019)

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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

Tools Required:

• OBD-II scanner
• Socket set
• Screwdrivers
• Multimeter
• Vacuum gauge

2. Inspect and Repair Air Intake System

1. Inspect air intake hoses:
   • Visually check for cracks or loose fittings.
   • Tighten or replace any damaged hoses.
2. Check and clean MAF sensor:
   • Disconnect the MAF sensor connector.
   • Remove the MAF sensor from the intake duct.
   • Use MAF cleaner and a soft brush to clean the sensor. Allow it to dry completely before reinstalling.
3. Reinstall MAF sensor and reconnect the connector.

3. Check Fuel System

1. Test fuel pressure:
   • Connect a fuel pressure gauge to the fuel rail.
   • Turn the ignition to the "On" position without starting the engine and check pressure readings against specifications.
   • Replace the fuel pump or fuel filter if pressure is low.
2. Inspect fuel injectors for leaks:
   • Remove the fuel rail and visually inspect injectors for fuel leakage.
   • Replace any faulty or leaking injectors.

4. Inspect Vacuum Lines

1. Check for vacuum leaks:
   • Visually inspect all vacuum lines connected to the intake manifold and throttle body.
   • Use a vacuum gauge to test line integrity. Replace any damaged lines.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0174 code.