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AutoCodes – GMC – P0171 2014 GMC Sierra

P0171 2014 GMC Sierra Code - Fuel Trim System Lean Bank 1

Quick Answer

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. Common causes include Dirty or Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0171 2014 GMC Sierra indicates Fuel Trim System Lean Bank 1.
Common causes
Common causes include Dirty or Restricted Air Filter, Dirty or Faulty Mass Air Flow (MAF) Sensor, Intake Air Leaks.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 523
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Jul 23, 2023
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Code P0171 2014 GMC Sierra Description

The Engine Control Module (ECM) controls a Closed Loop air/fuel metering system to provide the best possible combination of drivability, fuel economy, and emission control. The ECM monitors the Heated Oxygen Sensor (HO2S) signal voltage and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short-term fuel trim values. The short-term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine-tune the engine fueling. The long-term fuel trim values change in response to trends in the short-term fuel trim. The long-term fuel trim makes coarse adjustments to fueling to re-center and restore control to short-term fuel trim. The ideal fuel trim values are around 0 %. A positive fuel trim value indicates that the ECM is adding fuel to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel to compensate for a rich condition. The Diagnostic Trouble Code (DTC) will be set when the average long-term fuel trim weighted average value is greater or less than a calibrated value.
OBDII Code P0171 2014 GMC Sierra - Fuel Trim System Lean Bank 1 - AutoCodes.com
P0171 2014 GMC Sierra Code - Fuel Trim System Lean Bank 1
What does this mean?

What are the Possible Causes of the DTC P0171 2014 GMC Sierra?

  • Dirty or Restricted Air Filter
  • Dirty or Faulty Mass Air Flow (MAF) Sensor
  • Intake Air Leaks
  • Exhaust Gas Leaks
  • Fuel Contamination
  • Faulty or Clogged Fuel Injectors
  • Faulty Front Heated Oxygen Sensor
  • Ignition Misfiring
  • Low Fuel Pressure
  • Positive Crankcase Ventilation (PCV) Hose Leaks
  • Engine Control Temperature (ECT) inaccurate readings

How to Fix the DTC P0171 2014 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0171 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0171 is set in along with the P0174 code, it is highly likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the Mass Air Flow (MAF) Sensor. If the problem persists the MAF or Front Heated Oxygen (O2) Sensor will need to be replaced.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0171 2014 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0171 2014 GMC Sierra code?

Need more information on how to fix the P0171 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0171 2014 GMC Sierra Code

1. What does the OBDII code P0171 on a 2014 GMC Sierra mean?

The code P0171 indicates a lean condition in the fuel trim system on Bank 1 of the engine.

2. What are common symptoms of the P0171 code in a 2014 GMC Sierra?

Common symptoms of the P0171 code include rough idling, reduced engine performance, poor fuel economy, and the presence of a lean fuel mixture.

3. What are the possible causes of the P0171 code in a 2014 GMC Sierra?

Potential causes of the P0171 code include a vacuum leak, faulty mass airflow sensor, clogged fuel filter, malfunctioning oxygen sensor, or a problem with the fuel injectors.

4. How do I diagnose the P0171 code in a 2014 GMC Sierra?

Diagnosing the P0171 code typically involves inspecting for vacuum leaks, testing the mass airflow sensor, checking the fuel pressure, examining the oxygen sensor operation, and verifying the fuel injector functionality.

5. How can I repair the P0171 code in a 2014 GMC Sierra?

Repairing the P0171 code may involve fixing any vacuum leaks, replacing the mass airflow sensor, cleaning or replacing the fuel filter, addressing issues with the oxygen sensor, or cleaning or replacing the fuel injectors.

6. Can a dirty air filter trigger the P0171 code in a 2014 GMC Sierra?

Yes, a dirty air filter can obstruct the airflow to the engine, causing a lean fuel mixture and triggering the P0171 code.

7. Is it safe to continue driving with the P0171 code in a 2014 GMC Sierra?

It is not recommended to continue driving with the P0171 code as it can lead to engine damage and reduced fuel efficiency over time. It is best to address the issue promptly.

8. Will resetting the fault codes make the P0171 code disappear in a 2014 GMC Sierra?

Resetting the fault codes may temporarily clear the P0171 code, but if the underlying issue is not fixed, the code is likely to reappear after driving the vehicle for some time.

9. How can a professional mechanic help with the P0171 code in a 2014 GMC Sierra?

A professional mechanic can conduct a thorough diagnosis using specialized tools, accurately pinpoint the root cause of the issue, and perform the necessary repairs to resolve the P0171 code effectively.

10. Can a faulty catalytic converter trigger the P0171 code in a 2014 GMC Sierra?

Yes, a failing catalytic converter can cause an imbalance in the fuel mixture, leading to a lean condition and triggering the P0171 code.

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