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P0171 Pontiac

P0171 Pontiac - Fuel Trim System Lean Bank 1

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P0171 Pontiac Comments |  Add Comment
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
Help with Possible causes What does this mean?
Tech 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 replaced the air filter and clean the air flow meter. If the problem persist 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 Pontiac models:

2000-2001 Pontiac Transport
2000-2002 Pontiac Firebird
2000-2008 Pontiac Bonneville
2000-2008 Pontiac Grand Am
2000-2008 Pontiac Grand Prix
2000-2008 Pontiac Sunfire
2001-2008 Pontiac Aztek
2002-2008 Pontiac Montana
2000-2008 Pontiac Factory Service Bulletin OBDII Code P0171
Help with Tech Notes What does this mean?
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.)
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0171 Pontiac 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.

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PONTIAC Technical Service Bulletins for P0171 code
2007 PONTIAC G5 Fuel System, Gasoline:delivery:fuel Pump Details
2007 PONTIAC G5 072100 Fuel System, Gasoline:delivery:fuel Pump Details
2005 PONTIAC VIBE Engine And Engine Cooling Details
2005 PONTIAC VIBE Electrical System Details
2006 PONTIAC VIBE Engine And Engine Cooling Details
More Bulletins Help with Technical Service Bulletins What does this mean?
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