2000 Toyota Corolla MAF sensor testing. Using a scanner and labscope.
Trouble code P0171 in memory. How to determine what is causing the engine to run lean.

Engine Performance Diagnostics chapter 12 pages 5-8

symptoms 50

  • low power
  • hesitation
  • check engine light with a P0171 fault code

fix 50

  • clean dirty MAF sensor

test shown enh 50

  • how to test a mass airflow sensor
  • how to use a the oxygen sensor at wide open throttle to test fuel delivery
  • before and after cleaning scan data and scope measurements of the MAF sensor
  • throttle position sensor will not reach 100% on scan data
  • how to clean a MAF sensor

Tools used

  • lab scope
  • scan tool
  • back-probing tools
  • brake cleaner/MAF cleaner

end faq

{accordionfaq faqid=accordion15 faqclass="dotluvfaq help2 aligncenter headerbackground headerborder contentbackground contentborder round7" active=item0}


(Chapter 12) Mass Airflow Sensor Testing

Related videos:

SHow to troubleshoot a faulty MAF sensor (Mercedes Benz):


How to test a Ford MAF sensor:


How to identify and clean a dirty MAF sensor (Lexus):


How to identify and clean a dirty MAF sensor (Subaru):


False MAF sensor trouble codes (cracked air intake tube) GM:


MAF and lean codes from a missing air filter (P0171, P0174, P0102) :


How to test a 3-wire GM MAF sensor (wiring and sensor tests):


end faq

{accordionfaq faqid=accordion3 faqclass="darkhivefaq defaulticon headerbackground headerborder contentbackground contentborder round5" active=item0}

For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium. There is a 14 day free trial.

On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!