P0171 CHEVROLET - Fuel Trim System Lean Bank 1

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3

P0171 CHEVROLET Causes

  • Intake air leaks
  • Faulty front heated oxygen sensor
  • Ignition misfiring
  • Faulty fuel injectors
  • Exhaust gas leaks
  • Incorrect fuel pressure
  • Lack of fuel
  • Faulty Mass Air Flow (MAF) sensor
  • Incorrect Positive Crankcase Ventilation (PCV) hose connection
  • P0171 CHEVROLET Notes

    If the P0171 is combined with the P0174 code, it's very 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 air flow meter. If the problem persists the front oxygen (O2) sensor may need to be replaced.
    The P0171 code could also be caused may be caused by one or more of the following: debris on MAF sensor causing an incorrect reading, improper oil level, low or high fuel pressure or Engine Control Temperature (ECT) Sensor reading inaccurate.

    There is a factory service bulletin for the following Chevrolet models:

    2000 Chevrolet S-10
    2000-2008 Chevrolet Camaro
    2000-2008 Chevrolet Lumina
    2000-2008 Chevrolet Cavalier
    2000-2003 Chevrolet Impala
    2000-2003 Chevrolet Malibu
    2000-2003 Chevrolet Monte Carlo
    2000-2003 Chevrolet Silverado
    2000-2003 Chevrolet Suburban
    2000-2003 Chevrolet Tahoe
    2000-2003 Chevrolet Venture
    2001-2008 Chevrolet Express
    2002-2008 Chevrolet Astro
    2000-2003 Chevrolet Avalanche
    2000-2003 Chevrolet Trailblazer
    2003-2008 Chevrolet Blazer
    2003-2008 Chevrolet S-10
    2003-2008 Chevrolet Trailblazer EXT
    2000-2008 Chevrolet Factory Service Bulletin OBDII Code P0171

    2006 Trailblazer P0171

    User Submitted Video

    First diagnose P0171 CHEVROLET code

      Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

    Cost of diagnosing the P0171 CHEVROLET code

      Labor: 1.0

      The cost of diagnosing the P0171 CHEVROLET code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.

    P0171 CHEVROLET Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Excessive Fuel Consumption
  • P0171 CHEVROLET More Information

    Need more information on how to fix the P0171 CHEVROLET code?
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    P0171 CHEVROLET Description

    The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the ECM adds HO2S inputs to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

    P0171 CHEVROLET Information for specific Chevrolet models