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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamp pliers
• Check all vacuum hoses and connections for signs of wear or damage. Replace any that are cracked or loose.
• Use a vacuum gauge to test the intake manifold for leaks. If a leak is detected, reseal or replace components as necessary.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver set
• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor from the duct.
• Clean the sensor element using MAF sensor cleaner. Allow it to dry completely before reinstalling.
• If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, wrenches
• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position to check the fuel pressure. It should meet manufacturer specifications (usually around 30-40 psi).
• If the pressure is low, check the fuel pump, fuel filter, and fuel injectors for blockages or failures. Replace any faulty components.

5. Verify Electrical Connections

• Tools Required: Multimeter
• Use a multimeter to check the ECT sensor and MAF sensor wiring for continuity and shorts.
• Repair or replace any damaged wiring or connectors.