1999 Mercury Mountaineer 5.0 with a P0171 and P0174 DTC in memory. This is a great video on using fuel trim and freeze frame data to determine the cause of the lean condition.

Engine Performance Diagnostics chapter 4 pages 12-19

symptoms 50

  • intermittent no crank (starter doesn't engage)
  • erratic operation of the instrument cluster lights and gauges
  • new battery and starter was installed without a fix

fix 50

  • repair main block ground on the front of the engine

test shown enh 50

  • how to test the load side and control side of a starter
  • how to test the starter ground circuit

Tools used

  • incandescent test light
  • digital multimeter

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Starting, Charging and Battery system problems

Related videos:

Engine does not crank (bad block ground) - Cadillac:


Engine does not crank (seized alternator) -Mini Cooper:


Poor running, flashing CEL, no codes (bad computer ground) - Toyota:


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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!