How to Test the Crankshaft Position Sensor
(Ford 4.6L, 5.4L)

Symptoms of a BAD Ford Crank Sensor

You're probably ready to get this test started and over with, but, before you do...

You need to keep one very important thing in mind: When the crank sensor fails (goes BAD), the most obvious symptoms is a Cranks but Does Not Start condition due to no spark and no fuel injection.

With a BAD crank sensor on your Ford 4.6L or 5.4L vehicle you'll also see one of the following symptoms:

  1. If the vehicle is coil pack equipped: The ignition control module will not produce its PIP signal and thus, the PCM will not activate the fuel injectors.
    1. You can verify this by using a noid light to check for the fuel injector pulses.
    2. If the fuel injector pulses are present, the crank sensor is OK.
  2. If the vehicle is COP coil equipped: The PCM will not activate the fuel injectors.
    1. You can verify this by using a noid light to check for the fuel injector pulses.
    2. If the fuel injector pulses are present, the crank sensor is OK.
  3. No spark to any of the 8 engine cylinders.
    1. You can verify this by using a spark tester and checking each spark plug wire or COP coil.
    2. If spark is present (even if it's just at one cylinder), the crank sensor is OK.

OK, enough reading, let's get testing!

CKP TEST 1: Verifying the CKP Signal

The crank sensor on the 4.6L and 5.4L Ford engines is a two wire sensor that can be easily tested with your multimeter in AC Volts.

Remember, the battery must be fully charged for this test to produce an accurate result. Why? Well, because the strength of crank sensor's signal, that you'll be measuring with your multimeter, depends on the amount of RPMs your engine is turning as it's cranking.

The following test steps assume that you 4.6L or 5.4L pick up (car, van, or SUV) Cranks But Does Not Start (if you haven't already read the section: Symptoms of BAD Ford Crank Sensor, please do so now). OK, this is what you need to do:

  1. 1

    Disconnect the crank sensor's electrical connector and remove some of the plastic wire loom protector and/or the black electrical tape that shields/protects the two wires of the CKP sensor.

  2. 2

    Reconnect the connector to the crank sensor now and place your multimeter in Volts AC mode.

  3. 3

    Using a wire-piercing probe or another appropriate tool, probe the number 1 and number 2 wires of the crank sensor with the multimeter leads.

    To see what a what wire piercing probe tool looks like, click here: Wire Piercing Probe.

    It doesn't matter which multimeter lead (RED or BLACK) goes where, since the polarity of the leads doesn't matter.

  4. 4

    When everything has been set up and you're a safe distance from the engine, have your helper crank the engine as you observe the multimeter's AC Volts readings.

  5. 5

    If the CKP sensor is working correctly, the multimeter will register an an oscillating voltage between .5 to 1 Volt AC.

    Now, to be a bit more specific: your multimeter will not register a steady AC voltage. Instead, the reading will jump between .5 Volts AC to 1 Volt AC continually as the engine is cranking and only when the engine is cranking.

Alright, let's find out if you have a BAD CKP sensor on your hands or not. Choose from the CASES below that best match your specific results:

CASE 1: The multimeter registered the indicated AC voltage with the engine cranking: This result indicates that the CKP sensor is creating a good CKP signal and is working fine.

If you have confirmed that the crank sensor is OK but your Ford still doesn't start, take a look at the following tutorial for more testing suggestions:

  1. How to Test a No Start Condition (Ford 4.6L, 5.4L).

CASE 2: The multimeter DID NOT register the indicated AC voltage with the engine cranking: This confirms that the crank sensor is fried and is the cause of you Cranks but Does Not Start Condition.

If you'd like to buy the factory original Motorcraft crank sensor (and save), check out the section: Where to Buy the Crank Sensor and Save.

Ford Vehicles:

  • Crown Victoria
    • 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
  • E150, E250, E350
    • 1997, 1998, 1999, 2000, 2001, 2002
  • Expedition
    • 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009

Ford Vehicles:

  • Explorer (4.6L)
    • 2002, 2003, 2004, 2005
  • F150, F250
    • 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
  • Mustang (GT & Cobra)
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005

Ford Vehicles:

  • Thunderbird
    • 1994, 1995, 1996, 1997

Lincoln Vehicles:

  • Aviator
    • 2003, 2004, 2005
  • Mark VIII
    • 1993, 1994, 1995, 1996, 1997, 1998

Lincoln Vehicles:

  • Navigator
    • 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
  • Town Car
    • 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005

Mercury Vehicles:

  • Cougar
    • 1994, 1995, 1996, 1997
  • Grand Marquis
    • 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
  • Mountaineer (4.6L)
    • 2002, 2003, 2004, 2005

“I bought a perfect second car... a tow truck.”
Rodney Dangerfield

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