how to fix P0171 code in GMC Sierra T1XX (2019-Present)

Learn how to diagnose and fix P0171 engine lean condition in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal.
• Allow the vehicle to cool down if the engine has been running.

2. Inspect and Repair Air Intake System

• Tools Required: Screwdriver set, vacuum gauge
• Check all intake hoses and connections for leaks.
• Tighten any loose clamps or replace damaged hoses.
• If a leak is found, replace the affected component.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner spray, screwdriver
• Remove the MAF sensor from the air intake.
• Clean the sensor using MAF cleaner spray, following the instructions on the can.
• If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Test and Repair Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "On" position without starting the engine and check the fuel pressure.
• If the pressure is below specifications, inspect the fuel pump, fuel filter, and fuel pressure regulator.
• Replace any faulty components.

5. Inspect and Clean Fuel Injectors

• Tools Required: Injector cleaning kit or replacement injectors
• Use the injector cleaning kit to clean the fuel injectors or replace them if they are clogged or malfunctioning.