FAULTBASE
Error CodesASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/GMC/Sierra/T1XX (2019-Present)/how to fix P0171 code on GMC Sierra T1XX (2019-Present)

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

GMC Sierra T1XX (2019-Present)

Error Codes
Severity: highDifficulty: mediumError Code: P01712-4 hours
3 min read
557 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0171 lean fuel condition in GMC Sierra T1XX (2019-present). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0171
Affected Component
Engine
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical components.
  • ⚠Allow the engine to cool before working on the cooling system components.

Symptoms

  • •Check engine light illuminated
  • •Rough idle or stalling
  • •Decreased power during acceleration
  • •Poor fuel economy
  • •Unusual engine noises (hissing or whistling)
  • •Increased emissions

Diagnostic Steps

  1. 1Scan the vehicle’s OBD-II system for error codes and confirm P0171 is present.
  2. 2Inspect the air intake system for vacuum leaks, including hoses and the intake manifold.
  3. 3Check the Mass Air Flow (MAF) sensor for proper operation and cleanliness.
  4. 4Inspect the fuel system, including fuel pressure and fuel injectors for clogs or failures.
  5. 5Examine the engine coolant temperature sensor for accurate readings.
  6. 6Check for any recent modifications or repairs that may have affected the air-fuel mixture.

Solution

Solution

1. Preparation

  • Gather tools and parts.
  • Disconnect the vehicle’s battery to prevent electrical short circuits.

2. Inspect and Repair Air Intake System

  • Sub-steps:
    1. Use a visual inspection to check for any cracks or loose connections in the air intake hoses.
    2. If any leaks are found, replace the damaged hoses.
    3. Ensure that the air filter is clean; replace if necessary.

3. Clean the Mass Air Flow (MAF) Sensor

  • Tools Required: MAF cleaner spray
  • Sub-steps:
    1. Locate the MAF sensor in the air intake duct.
    2. Disconnect the electrical connector from the MAF sensor.
    3. Remove the MAF sensor from the duct.
    4. Spray the MAF sensor with MAF cleaner; avoid touching the sensor elements.
    5. Allow it to dry completely before reinstalling.

4. Check and Adjust the Fuel System

  • Sub-steps:
    1. Use a fuel pressure gauge to check the fuel pressure at the fuel rail.
    2. If the pressure is low, check the fuel pump operation and replace if necessary.
    3. Inspect fuel injectors for clogs; clean or replace as needed.

5. Replace Engine Coolant Temperature Sensor (if necessary)

  • Sub-steps:
    1. Locate the engine coolant temperature sensor.
    2. Disconnect the electrical connector.
    3. Remove the sensor using the appropriate socket.
    4. Install the new sensor and reconnect the connector.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Socket set
  • •Fuel pressure gauge
  • •MAF cleaner spray
  • •Screwdrivers

Parts Required

  • •Air intake hoses (if damaged)
  • •Air filter (if dirty)
  • •MAF sensor (if faulty)
  • •Fuel pump (if pressure is low)
  • •Fuel injectors (if clogged)
  • •Engine coolant temperature sensor (if faulty)

Additional Information

Error Code
P0171
Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
high
Tools Required
5 items
Parts Required
6 items

Related Faults

  1. my GMC Sierra T1XX (2019-Present) has high oil consumption, is that normal?

    Learn how to diagnose and fix high oil consumption issues in GMC Sierra T1XX (2019-Present). Step-by-step guide with diagnostic procedures and repair instructions.

    Engine6 symptoms

  2. why does my GMC Sierra T1XX (2019-Present) stall when I come to a stop?

    Learn how to diagnose and fix stalling issues in GMC Sierra T1XX (2019-Present). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Engine6 symptoms

  3. what causes my GMC Sierra to have low oil pressure warnings

    Learn how to diagnose and fix low oil pressure warnings in GMC Sierra. Step-by-step guide with diagnostic procedures and repair instructions.

    Engine6 symptoms

  4. why is my GMC Sierra using so much oil

    Learn how to diagnose and fix excessive oil consumption in GMC Sierra. Step-by-step guide with diagnostic procedures and repair instructions.

    Engine6 symptoms

  5. why does my GMC Sierra T1XX (2019-Present) smell like burning oil?

    Learn how to diagnose and fix the burning oil smell in GMC Sierra T1XX (2019-Present). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Engine6 symptoms

  6. why does my GMC Sierra T1XX (2019-Present) have low oil pressure?

    Learn how to diagnose and fix low oil pressure in GMC Sierra T1XX (2019-Present). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Engine6 symptoms

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation