How to troubleshoot a no fuel pressure problem on any car. Is it the fuel pump, relay or wiring? Computer problem? Cam or Crank sensor problem? These questions and many others I will answer in this video.

The car being tested is a 2001 Ford Explorer with a P0231 Fuel Pump Secondary Circuit Low trouble code.

Engine Performance Diagnostics chapter 15

Topics discussed


  • no start


  • replace faulty fuel pump relay

test shown

  • how to test fuel pressure
  • how to use the check engine light during cranking as a guide
  • how to use the tachometer during cranking as a guide
  • how to test a fuel pump relay
  • how to determine load and control sides of a relay
  • how to determine if the computer is controlling the FP relay

Tools used

end faq

Related videos:

How to test fuel pressure, injector pulse and spark with basic tools - Honda:

Fuel pump electrical circuit diagnosis (no fuel pressure testing) GM:

How to test an electric fuel pump (no fuel psi testing) Ford:

Fuel Pump Electrical Circuits Description and Operation:

end faq



(Chapters 14, 15,16) Fuel Delivery and Fuel Pressure Testing

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.

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