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

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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Basic socket set, vacuum gauge
• Instructions:
  1. Remove the engine cover (if applicable) using a socket.
  2. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  3. Use a vacuum gauge to test for leaks; if a leak is found, replace the affected hose or component.
  4. Reassemble and secure all connections.

3. Check and Clean MAF Sensor

• Tools Required: MAF sensor cleaner
• Instructions:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector from the sensor.
  3. Remove the MAF sensor using a screwdriver or socket.
  4. Spray the MAF sensor with MAF cleaner, ensuring not to touch the sensing element.
  5. Allow it to dry completely before reinstalling it.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Instructions:
  1. Locate the fuel rail and remove the fuel pressure test port cap.
  2. Connect the fuel pressure gauge to the test port.
  3. Turn the ignition to the "ON" position (without starting the engine) to check the pressure reading.
  4. Compare the reading to the manufacturer’s specifications; if low, check the fuel pump and filter.

5. Inspect Fuel Injectors

• Tools Required: Noid light (for testing)
• Instructions:
  1. Disconnect the fuel injector connectors.
  2. Connect a noid light to each injector connector and crank the engine.
  3. If the noid light does not flash, check the injector driver circuit; replace or repair as necessary.
  4. Reconnect all injector connectors after testing.