AutoCodesChevrolet – P0174 Chevrolet

P0174 Chevrolet 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 Chevrolet 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 180,477
How popular is this code, among other codes? High
Table of contents Created and updated by William Orellana on Aug 21, 2022
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Code P0174 Chevrolet 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 Chevrolet - Fuel Trim System Lean Bank 2 - AutoCodes.com
P0174 Chevrolet Code - Fuel Trim System Lean Bank 2

What are the Possible Causes of the DTC P0174 Chevrolet?

  • 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 Chevrolet?

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 Chevrolet 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 Chevrolet code?

Need more information on how to fix the P0174 Chevrolet code? Get Access to Factory Service Manuals

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Get the P0174 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet 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 Chevrolet Code

1. What are common symptoms of OBDII code P0174 on a Chevrolet indicating a lean fuel trim system in bank 2?

- Common symptoms include rough idle, lack of power, engine misfires, and possibly the illumination of the check engine light.

2. What are the typical causes of OBDII code P0174 on a Chevrolet related to a lean fuel trim system in bank 2?

- Causes may include a vacuum leak, faulty oxygen sensor, fuel pump issues, clogged fuel injectors, or a malfunctioning mass airflow sensor.

3. How can I diagnose the specific cause of OBDII code P0174 on my Chevrolet with a lean fuel trim system in bank 2?

- Diagnosis may involve using a scan tool to monitor live data, inspecting for vacuum leaks, testing oxygen sensors, checking fuel pressure, and performing a smoke test.

4. Is it safe to continue driving my Chevrolet with OBDII code P0174 indicating a lean fuel trim system in bank 2?

- It is generally not recommended to drive the vehicle for an extended period with this issue, as it can lead to engine damage or other costly repairs.

5. What are some DIY repair tips for addressing OBDII code P0174 on a Chevrolet with a lean fuel trim system in bank 2?

- DIY repair tips may include checking and replacing damaged vacuum hoses, cleaning or replacing the mass airflow sensor, inspecting the air filter, and ensuring proper fuel system operation.

6. How much does it typically cost to repair OBDII code P0174 on a Chevrolet related to a lean fuel trim system in bank 2?

- The cost of repairs can vary depending on the specific cause, but it may range from a few hundred to over a thousand dollars if professional help is required.

7. Can a dirty or clogged fuel filter cause OBDII code P0174 on a Chevrolet with a lean fuel trim system in bank 2?

- Yes, a dirty or clogged fuel filter can restrict fuel flow and lead to a lean condition, triggering the P0174 trouble code.

8. Will resetting the check engine light resolve OBDII code P0174 on a Chevrolet with a lean fuel trim system in bank 2?

- Simply resetting the check engine light will not fix the underlying issue causing the code. It is important to diagnose and address the root cause of the problem.

9. What role does the fuel trim system play in the operation of a Chevrolet experiencing OBDII code P0174 for a lean condition in bank 2?

- The fuel trim system is responsible for adjusting the air-fuel mixture to maintain proper engine performance and emissions. A lean condition in bank 2 indicates an imbalance that needs to be corrected.

10. Is it advisable to seek professional help for diagnosing and repairing OBDII code P0174 on a Chevrolet with a lean fuel trim system in bank 2?

- If you are not familiar with automotive diagnostics and repairs, seeking professional help from a certified mechanic or dealership is recommended to accurately diagnose and fix the issue.

Discuss the causes and fixes for P0174 Chevrolet OBDII Code

  • 2006 Chevy Uplander check engine light ON. Code reads P0171. That's the only code. Cleaned/inspected injectors. They seem OK. Cleaned mass air flow sensor, also seems OK. Cleaning the throttle body next. Also, have to step on the gas to get it to start..... maybe it's the TPS sensor (throttle position sensor) or ECT sensor (engine temp control sensor)? Need help/ advice? Anyone else seen this problem?

  • A code P0171 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor Possible Solutions A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain. So, possible solutions include: Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect all vacuum and PCV hoses, replace/repair as required Inspect all hoses and connections in the air intake system Inspect and/or test the intake manifold gaskets for leakage Check for a dirty fuel filter and proper fuel pressure Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool If you have access, you may want to run a smoke test

  • This is what I found, hope it helps. Good luck.

  • So basically I'm Sherlock Holmes at this point trying to investigate what the he'll is wrong with my car, I have a 2000 chevy camaro, 3.8 liter v6 engine...here are my codes: po174 lean bank 2(this code appears twice), code po449, I believe that's the fuel tank pressure sensor and a po452, EVAP circuit malfunction.

    Here are my symptoms:
    1)Rough idle then smooths out at start.
    2) great loss of power, anything over 75mph is a strain.
    3) consumes fuel like crazy.
    4) low compression

    I will say that I replaced the MAF sensor about 6 months ago, but got the codes read at auto zone and they said that it was likely a faulty MAF. I also just replaced the fuel pump with a new fuel filter with it and its still running the same.

    I'm at a lost, anything at this point would help greatly, thanks!

  • You need to check your cats, take out o2 sensors and see if everything improves.

  • We have a 2012 Chevy Impala that wont pass inspection. When we clear the P0174 code and drive the car for 50 Miles all the sensor monitors go from Inc to OK then the CEL comes back on with the P0174 Code. We have replaced the Air Cleaner Element, cleaned the MAF and for the last expedition put 2 bottles of injector cleaner into a full tank of High Octane Fuel. Why do all the Sensor Monitors reset to OK then the CEL come back on?

  • Could be clogged fuel injectors, but it may take more than a fuel tank of gas and more fuel injector cleaner to clean the injectors.

    There is a factory service bulletin with the following information:

    CAUSE
    Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.

    CORRECTION
    Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline. For further information on Top Tier detergent gasoline and fuel retailers.

  • Thank you for replying however I can't seem to get your whole reply or the procedure!

    I found it on the net, cheers for your help I will give the injectors a poverty clean by taking them out of the car.

  • 02 express van 2500 with 5.7 vortec po 174 code starts good drives good no problem, repaired some vac leaks. replaced fuel filter and the spider fuel assy. good fuel pressure 50psi and holds at 40psi, when vet is turned off.

  • i got a 2019 chevy colorado over the weekend i changed a bad injector on bank 2 cylinder 2 all the codes went away i get in it the moring to drive to work i get system too lean in bank 2 i looked ever where to find a leak cant find one any help

    • Do you have any other symptoms? If you don't, then try clearing the code first and driving your vehicle for a couple of days.

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