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

Solution

1. Preparation

• Gather tools and parts required for the repairs.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool completely before starting any work.

2. Inspect and Repair Air Intake System

• Inspect hoses and connections:

  • Visually check all hoses for cracks or leaks.
  • Tighten any loose connections.
  • If any components are damaged, replace them.

• Clean MAF Sensor:

  • Remove the MAF sensor using a Torx screwdriver.
  • Use MAF sensor cleaner to gently clean the sensor element.
  • Allow it to dry completely before reinstalling.

3. Check Fuel System

• Fuel Pressure Test:

  • Connect a fuel pressure gauge to the fuel rail test port.
  • Turn the ignition to the "on" position without starting the engine and check the fuel pressure.
  • It should be within the manufacturer's specifications (typically around 50-60 psi).
  • If pressure is low, inspect the fuel pump and fuel filter for issues.

• Inspect Fuel Injectors:

  • Remove the fuel rail with injectors attached.
  • Check for leaks and proper operation by applying voltage to the injectors.
  • Clean or replace any clogged or malfunctioning injectors.

4. Repair Vacuum Leaks

• Inspect and Replace Vacuum Lines:

  • Check all vacuum lines for cracks or disconnections.
  • Replace any damaged vacuum hoses.

• Inspect Intake Manifold:

  • Remove the intake manifold, if necessary, to inspect the gasket for leaks.
  • Replace the intake manifold gasket if it is worn or damaged.

5. Reassemble and Test

• Reassemble any components that were removed during the inspection and repair process.
• Reconnect the negative battery terminal.
• Start the engine and let it idle to check for any abnormalities.