P0171 TOYOTA - Air/Fuel Mixture System Lean Bank 1
P0171 TOYOTA 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
First diagnose P0171 TOYOTA code
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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.
P0171 TOYOTA 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 replace the air filter and clean the air flow meter. If the problem persists the front oxygen (O2) sensor may need to be replaced.There is a factory service bulletin for the following Toyota models:
2005–2007 Toyota Avalon
2007–2008 Toyota Camry
2005-2007 Toyota Avalon, 2007-2008 Toyota Camry Service Bulletin OBDII Code P0171
2005-2006 Toyota Corolla
2005-2006 Toyota Corolla Service Bulletin OBDII Code P0171
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Cost of diagnosing the P0171 TOYOTA code
Labor: 1.0
The cost of diagnosing the P0171 TOYOTA 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 P0171 TOYOTA code detected?
- Fuel injection system does not operate properly.- The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)
P0171 TOYOTA Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0171 Toyota Description
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).

P0171 TOYOTA More Information
Need more information on how to fix the P0171 TOYOTA code?Get Access to Factory Service Manuals
P0171 Toyota Information for specific Toyota models
- P0171 1997 TOYOTA CAMRY
- P0171 1998 TOYOTA CAMRY
- P0171 1999 TOYOTA CAMRY
- P0171 2000 TOYOTA CAMRY
- P0171 2001 TOYOTA CAMRY
- P0171 2001 TOYOTA CAMRY
- P0171 2006 TOYOTA CAMRY
- P0171 2007 TOYOTA CAMRY
- P0171 2008 TOYOTA CAMRY
- P0171 2009 TOYOTA CAMRY
- P0171 2010 TOYOTA CAMRY
- P0171 2011 TOYOTA CAMRY
- P0171 2001 TOYOTA COROLLA
- P0171 2002 TOYOTA COROLLA
- P0171 2003 TOYOTA COROLLA
- P0171 2004 TOYOTA COROLLA
- P0171 2005 TOYOTA COROLLA
- P0171 2006 TOYOTA COROLLA
- P0171 2000 TOYOTA ECHO
- P0171 2001 TOYOTA ECHO
- P0171 2002 TOYOTA ECHO
- P0171 2001 TOYOTA HIGHLANDER
- P0171 2002 TOYOTA HIGHLANDER
- P0171 2003 TOYOTA HIGHLANDER
- P0171 2004 TOYOTA HIGHLANDER
- P0171 2005 TOYOTA HIGHLANDER
- P0171 2006 TOYOTA HIGHLANDER
- P0171 2007 TOYOTA HIGHLANDER
- P0171 2004 TOYOTA PRIUS
- P0171 2005 TOYOTA PRIUS
- P0171 2006 TOYOTA PRIUS
- P0171 2007 TOYOTA PRIUS
- P0171 2008 TOYOTA PRIUS
- P0171 2009 TOYOTA PRIUS
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