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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold and replace any that are cracked or disconnected.
  2. Use a smoke machine or carburetor cleaner to identify leaks in the intake system.
  3. Tighten any loose clamps on intake hoses.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the MAF sensor from the air intake duct using a Torx or socket wrench.
  3. Clean the sensor with MAF cleaner spray and let it dry completely. If damaged, replace it with a new one.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the ON position (do not start the engine) and check the fuel pressure reading against manufacturer specifications (usually around 40-50 PSI).
  3. If the pressure is low, check the fuel pump and fuel filter for blockage or failure.
  4. Replace the fuel filter if necessary.

5. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly to access the fuel injectors.
  2. Inspect each injector for clogs or leaks. Clean them using a specialized injector cleaner or replace if needed.
  3. Reinstall the fuel rail and ensure all connections are tight.