AutoCodes – GMC – P0174 2016 GMC Sierra

P0174 2016 GMC Sierra Code - Fuel Trim System Lean Bank 2

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: P0174 2016 GMC Sierra indicates Fuel Trim System Lean Bank 2.
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 307

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 21, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0174 2016 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 P0174 2016 GMC Sierra - Fuel Trim System Lean Bank 2 - AutoCodes.com — P0174 2016 GMC Sierra Code - Fuel Trim System Lean Bank 2

What does this mean?

What are the Possible Causes of the DTC P0174 2016 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

How to Fix the DTC P0174 2016 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 P0174 code means that more air than gasoline is detected in the exhaust gases exiting the combustion chamber. If the P0174 is set in along with the P0171 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.

Click Here to Learn What is Bank 1 and Bank 2

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0174 2016 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.

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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 P0174 2016 GMC Sierra Code

1. What does the OBDII code P0174 mean on a 2016 GMC Sierra?

P0174 indicates that the fuel trim system on Bank 2 is running too lean, meaning the air-to-fuel mixture has too much air or not enough fuel on that side of the engine.

2. What are the common symptoms of the P0174 code on a 2016 GMC Sierra?

Symptoms may include a check engine light, reduced engine performance, rough idling, engine misfires, and increased fuel consumption.

3. What causes the P0174 code on a 2016 GMC Sierra?

Common causes include a vacuum leak, a faulty mass air flow (MAF) sensor, a clogged fuel injector, a failing oxygen sensor, or low fuel pressure.

4. Can a dirty mass air flow (MAF) sensor trigger the P0174 code?

Yes, a dirty or malfunctioning MAF sensor can cause incorrect air-to-fuel ratio calculations, leading to a lean condition and triggering the P0174 code.

5. How can I diagnose the P0174 code on my 2016 GMC Sierra?

Check for vacuum leaks, inspect the MAF sensor, test the fuel pressure, examine the oxygen sensors, and inspect the intake manifold gaskets for leaks or damage.

6. Is it safe to drive my 2016 GMC Sierra with the P0174 code?

While the vehicle may still be drivable, driving with this code can cause engine damage over time due to the lean condition. It's best to address the issue promptly.

7. How much does it cost to repair the P0174 code on a 2016 GMC Sierra?

Repair costs vary depending on the cause. For example, cleaning a MAF sensor may cost under $50, while replacing injectors or fixing a vacuum leak could cost a few hundred dollars.

8. Can a bad oxygen sensor cause the P0174 code on a 2016 GMC Sierra?

Yes, a failing oxygen sensor can send incorrect data to the engine control module (ECM), leading to a lean condition on Bank 2.

9. Will replacing the fuel filter fix the P0174 code?

If the code is caused by low fuel pressure due to a clogged fuel filter, replacing it may resolve the issue. However, further diagnosis is recommended.

10. What tools are needed to troubleshoot the P0174 code on a 2016 GMC Sierra?

Tools like an OBDII scanner, a fuel pressure gauge, and a vacuum gauge are commonly used to diagnose and resolve the P0174 code.