GMC Sierra T1XX (2019-Present) what does a P0171 code mean

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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Repair Air Intake Components

• Sub-steps:
  1. Remove the engine cover if necessary.
  2. Inspect the air intake duct for any signs of cracks or disconnections.
  3. Tighten or replace any loose or damaged clamps or hoses.
  4. Clean the MAF sensor with MAF sensor cleaner to remove dirt and debris.

3. Check and Repair Fuel System

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position but do not start the engine. Record the fuel pressure reading.
  3. Compare the reading with the manufacturer's specifications. If it is low, check the fuel pump and filter.
  4. Replace the fuel filter if it is clogged or dirty.

4. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect vacuum hoses for damage or disconnection.
  2. Use a smoke machine or carburetor cleaner to test for leaks in the vacuum system.
  3. Replace any damaged hoses or fittings.

5. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0171 code.
  3. Take the vehicle for a test drive to ensure the issue is resolved.

Tools Required:

• OBD-II scanner
• Fuel pressure gauge
• Socket set
• Torque wrench
• MAF sensor cleaner
• Vacuum gauge (optional)
• Smoke machine (optional)

Parts Required:

• Air intake duct (if damaged)
• Fuel filter (if necessary)
• Vacuum hoses (if damaged)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical systems.
• Allow the engine to cool before inspecting components.