how to fix P0174 code in Toyota Corolla E210 (2019-2024)

Learn how to diagnose and fix P0174 engine lean condition in Toyota Corolla E210 (2019-2024). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts before starting the repair.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Repair Air Intake System

• Tools Required: Screwdriver set, vacuum gauge, flashlight
• Check for any cracks or disconnections in the intake hoses.
• Replace any damaged hoses or clamps.
• Ensure the air filter is clean; replace if necessary.

3. Fuel Pressure Check

• Tools Required: Fuel pressure gauge
• Attach the fuel pressure gauge to the fuel rail test port.
• Turn on the ignition without starting the engine and check the fuel pressure.
• If the pressure is below specifications (usually around 43-50 psi), inspect the fuel pump and fuel filter for issues.

4. Clean MAF Sensor

• Tools Required: MAF cleaner spray
• Remove the MAF sensor from the air intake.
• Spray the MAF cleaner on the sensor element and let it dry completely before reinstalling.

5. Inspect and Test Fuel Injectors

• Tools Required: Injector cleaning kit, multimeter
• Remove the fuel injectors and check for clogs or leaks.
• Use an injector cleaner kit to clean them if necessary.
• Test the resistance of each injector using a multimeter; replace any faulty injectors.

6. Check Oxygen Sensors

• Tools Required: O2 sensor socket
• Inspect the wiring and connections for both upstream and downstream oxygen sensors.
• Use a multimeter or OBD-II scanner to test for proper voltage and signal output; replace any faulty sensors.