P0171 system is too lean on bank one?

2000 TOYOTA AVALON
125,000 MILES • 6 CYL • FWD • AUTOMATIC
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ANNETTE TAYLOR
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  • 1 POST
I have a computer code after I scanned my Avalon XLS. It is P0171 system is too lean on bank one
Jul 27, 2009 at 6:44 PM
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SQM
  • ASE Certified Mechanic
  • 6,383 POSTS
  • ASE Certified Mechanic
Hello,

This code P0171 can be triggered by simply a oxygen sensor. However it can be the reason of few other issues as well.

Could be due to restriction in the air induction system.
Blockage in the injector.
Faulty Mass air flow sensor.
Fuel pressure.

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor
https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor


I have attached the diagnostics for that code. This will help you determine the issue and pin point the problem.

Please let me know of any questions.

Thank you.
Aug 24, 2021 at 10:57 PM
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