P0171 CHEVROLET - Fuel Trim System Lean Bank 1
P0171 CHEVROLET Possible 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
How do I fix code P0171 CHEVROLET?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 connector's pins.
The P0171 code could also be caused may be caused by one or more of the following: debris on the MAF sensor causing an incorrect reading, improper oil level, low or high fuel pressure, or Engine Control Temperature (ECT) Sensor reading inaccurate.
There are Factory Service Bulletins for the following Chevrolet models:
2000-2013 Chevrolet All Models:
2000-2013 Chevrolet Factory Service Bulletin OBDII Code P0171
2005-2006 Chevrolet Impala
2005-2006 Chevrolet Monte Carlo
2005-2006 Chevrolet TrailBlazer Models
2007 Chevrolet Avalanche
2007 Chevrolet Suburban
2007 Chevrolet Tahoe
Chevrolet Factory Service Bulletin OBDII Code P0171
2006 Trailblazer P0171
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Cost of diagnosing the P0171 CHEVROLET code
Labor: 1.0The cost of diagnosing the P0171 CHEVROLET code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected?- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0171 CHEVROLET DescriptionThe 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.
More InformationNeed more information on how to fix the P0171 CHEVROLET code?
Get Access to Factory Service Manuals
Information for specific Chevrolet models
Need more help?Get the P0171 Chevrolet code diagnosed by a professional: Find a repair shop in your area
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