AutoCodesGMC – P0174 GMC

P0174 GMC 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 GMC 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 85,813
How popular is this code, among other codes? Medium
Table of contents Created and updated by William Orellana on Aug 21, 2022
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Code P0174 GMC 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 GMC - Fuel Trim System Lean Bank 2 - AutoCodes.com
P0174 GMC Code - Fuel Trim System Lean Bank 2

What are the Possible Causes of the DTC P0174 GMC?

  • 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 GMC?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0174 GMC 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 P0174 GMC code?

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Information for Specific GMC Models

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 GMC Code

1. What are the common symptoms of OBDII code P0174 GMC?

- Common symptoms include rough idling, poor acceleration, decreased fuel efficiency, and potential engine misfires.

2. What does the OBDII code P0174 GMC indicate?

- The code indicates a lean condition in the fuel trim system on Bank 2 of the engine, typically caused by a lack of fuel delivery relative to the amount of air entering the engine.

3. What are some potential causes of OBDII code P0174 GMC?

- Common causes include a vacuum leak, faulty oxygen sensor, clogged fuel filter, malfunctioning mass airflow sensor, or a leaking intake manifold gasket.

4. How can I diagnose the cause of OBDII code P0174 GMC?

- Diagnosing the issue may involve conducting a visual inspection for damaged hoses, using a scan tool to monitor data from oxygen sensors and fuel trims, and performing a smoke test to detect vacuum leaks.

5. Can a clogged fuel injector cause OBDII code P0174 GMC?

- Yes, a clogged or malfunctioning fuel injector on Bank 2 can disrupt the fuel delivery balance, leading to a lean condition and triggering the P0174 code.

6. How can I repair OBDII code P0174 GMC?

- Repair options may include replacing faulty oxygen sensors, fixing vacuum leaks, cleaning or replacing clogged fuel filters, addressing fuel injector issues, or repairing intake manifold gasket leaks.

7. Is it safe to continue driving with OBDII code P0174 GMC?

- It is not recommended to continue driving with this code unresolved, as it can lead to further engine damage and potentially cause more costly repairs down the line.

8. Can a dirty air filter trigger OBDII code P0174 GMC?

- A dirty air filter can restrict airflow to the engine, causing an imbalance in the air-fuel mixture and potentially triggering the P0174 code if left unaddressed.

9. Will resetting the OBDII code P0174 GMC make it go away permanently?

- Resetting the code may temporarily clear the warning light, but if the underlying issue causing the lean condition is not fixed, the code is likely to reappear during driving conditions.

10. Should I seek professional help to diagnose and repair OBDII code P0174 GMC?

- If you are unsure about diagnosing or repairing the issue yourself, it is advisable to seek professional help from a qualified mechanic to ensure the problem is properly identified and resolved.

Discuss the causes and fixes for P0174 GMC OBDII Code

  • 2000 gmc savanna 2500 5.7 have had the intake gaskets replaced new plugs and wires ran good for a week now acts like it has a miss and were getting 4 codes po121,po161,p0174,p1345 any ideas

  • P0121 GMC - Throttle Position Sensor 1 Performance
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    P0161 GMC - HO2S Heater Performance Bank 2 Sensor 2
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    P1345 GMC - Crankshaft Position-Camshaft Position Correlation
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    Only the P0161 code could be related to the the P0174. You should start by inspecting the sensor connector and the intake gasket installation

  • my name is jim I have a 2000 gmc Yukon 5.3 vortec engine it is also 4x4 the engine codes that are coming up are po171 and po174 both at the same time I clear these codes and these codes come back within a day or so????????

  • Unfortunately there are a few things that could cause the P0171 and P0174, but should not be related to the 4x4 system.

    Common problems for the P0171 and P0174 are:
    - Intake leaks (broken hoses or gasket)
    - Clogged injectors ( you could try using a fuel injector cleaner or/and high octane gas)

  • Hola yo tengo una 2002 GMC sierra y empezó a fallar y saco el código po300 y po174 y las bujías del lado del pasajero las llena de humo y también los sensores de oxígeno del ado del pasajero que me aconsejan

  • El problem mas comun cuando se tienen los dos codigos es el "Intake Manifold Gasket". Tambien este seguro que el filtro de aire y de gas esta limpios.

  • Gmc acadia slt awd se quiere apagar en baja cuando detengo el vehículo y el ralenti se pone inestable

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