How To Test a Ford Mustang Crank Sensor

How To Test a Ford Mustang Crank Sensor


The Mustang crank sensor in your Ford is a variable sensor that reads the crankshaft position and how fast the crankshaft is moving.  Your Ford Powertrain Control Module or PCM is a computer that uses this information to properly operate your 4.6 liter engine. When this variable reluctance sensor starts to fail, it can stop your Mustang from starting. When your engine computer doesn’t have this signal, your engine will shut off.

If you happen to own a Ford Mustang GT with an automatic transmission, this is a huge problem. If your engine shuts off at speed because of the crank sensor, you’ll lose power steering and brake assist. This is one of the main reasons why when your 4.6L Mustang crank sensor is having a problem, you should stop driving right away.

Today I’ll be showing you how to test your Mustang crank sensor in a 2003 Mustang with a 4.6 liter engine in it. Because this sensor is a variable reluctance style, as opposed to an optical or hall effect sensor, there’s just two wires. The testing procedure for your Mustang crank sensor is easy to do when you have a digital multimeter.

How To Test a Ford Mustang Crank Sensor 1

This DIY tutorial is the same for the normal Mustang GT as well as the BOSS GT models. Your 4.6 liter crank angle sensor generates it’s own signal which is read by your multimeter as an AC voltage signal.

When you insert your ignition into your Ford Mustang and go to start it, your starter will rotate the engine. Your Mustang crank sensor picks up on this movement and sends this data directly to your ignition control module and Powertrain Control Module. Your Mustang ignition control module sends a PIP or Profile Ignition Pickup signal which is used by your PCM to fire the fuel injectors properly.

Your ignition coils are then activated and being sending spark power to your spark plugs for each cylnder. For the 4.6 liter engine in your Mustang, there’s several version of the Mustang and engine type.

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Depending on your year of Ford Mustang, the symptoms from a failed crank sensor will vary. Because the 4.6 liter engine enjoyed a lengthy production run, you are going to have different variations of the engine.

Symptoms of a failed Mustang crank sensor

If your Mustang is equipped with ignition coil packs and wires in a traditional sense, you’ll need to use an automotive noid light to test your injectors. This is because your ignition control module will not create a PIP signal.

Mustang Boss engine
Mustang Boss engine

If your Mustang is equipped with coil on plug coils, this process is slightly different. You can still test the crank sensor remotely using a noid light however. Here are some of the symptoms to a problematic Mustang crank sensor.

  • Hard to Start Condition
  • Mustang will not start
  • Intermittent engine shutting off
  • Check Engine Light ON

The check engine light can also be triggered through a weak battery in your Ford Mustang. Because this Mustang crank sensor is not powered, your engine computer can confuse a failed sensor with a lack of cranking power from your battery. Before continuing make sure your battery is fully charged.

How To Test Your Mustang crank sensor

Because this part of the test involves you cranking your engine, we recommend that you remove your spark plugs. This allows you to manually crank the engine over by hand to test your crank angle sensor. Doing it this way also eliminates the chance of injury or damage to your tools, because your engine isn’t starting or try to start.

Locate your crank angle sensor and pierce both wires using your multimeter leads. Remember to make sure that your battery is charged fully, and that you have no issues with your electrical system.

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There’s no need to worry about the polarity or which probe of your multimeter needs to go where. Just make sure that both leads are piercing the Mustang crank sensor wires and getting good contact.

Because your 4.6L spark plugs have been removed, it should be easier to manually crank your engine using a crank wrench or 1/2 inch drive. Insert your Mustang key and turn to the “ON” position, so that your engine sensors are powered.

Manually turn your engine and monitor your multimeter voltage. As you turn your crankshaft over you should see a DC voltage that jumps from .5 Volts AC to 1 Volt of AC power. Remember that you need to have the Ford Mustang crank sensor plugged in, and that you are piercing the wires with your probes of your multimeter.

In the event your Ford crank angle sensor does not return this signal or there’s no response, you need a replacement crank sensor. Have any questions about this Mustang crank angle sensor tutorial? Leave us a comment below and let us know!