How To Test a Ford Focus Crank Sensor

How To Test a Ford Focus Crank Sensor


The Focus crank sensor in your Ford is there to read the position of your crankshaft. By reading the teeth on your crankshaft trigger plate, your Ford engine computer can determine engine speed. Unlike many other crank sensors that operate as a hall effect style sensor, the Focus crank sensor in your 2.0 liter Ford is a variable type with just two pins in it. This crank angle sensor determines the position and speed of your crankshaft and sends the signal to your Ignition Control Module or ICM.

Without the proper signal from your Focus crank sensor, your engine will not run properly. If your Focus won’t start, one of the common causes is a failed Focus crank sensor. Today I’ll be showing you how to test your Ford crank position sensor in a 2007 Ford Focus ZX4 with a 2.0 liter ZETEC engine in it.

In order to complete this testing guide for your Focus crank sensor, you will need to use a digital multimeter. Problems with your crank angle sensor can cause other issues as well, here’s a few of the common symptoms below.

Common Focus problems from a bad crank sensor

We’ve already talked about your Focus not starting, but there are other issues as well because of the variable style of this sensor. Here are just some of the common Focus crank sensor symptoms below.

  • Long starting time
  • Engine misfire
  • Focus starting problems
  • Engine shuts off randomly
  • Focus check engine light ON

When you see your Focus check engine light turned on, you’ll need a OBDII scan tool to check the code. If this code returns as a crank angle sensor related issue, you can proceed to test the Focus crank sensor using this guide.

How To Test a Ford Focus Crank Sensor 3

When you have issues with your Focus crank sensor, it’s best to not drive your vehicle.

This is especially true if you own a Focus with an automatic transmission. Because your engine will shut off if it loses the crank signal, this can be very dangerous.

If your Ford Focus loses the crank signal while you are driving the engine will shut off unexpectedly. This will leave you traveling down the road without power brakes or power steering.

There are several Ford part numbers for your Focus crank sensor. This ZETEC crank angle sensor part number is 94BF6C315AA, F5RZ6C315A, or F5RZ6C315AA. You can also find this part number under a Mazda part number as well, and that one is YF0918221.

Where is my Ford Focus crank sensor located?

This sensor is mounted to the front of your ZETEC engine near your crank pulley. This sensor is there to read the teeth on the crank plate. In order for you to test this part, you will need to track back the Focus crank sensor wiring to the two pin connector.

Focus crank sensor

In this year range your Focus crank sensor is on the passenger side of the vehicle. If you happen to own a SVT version of the Focus, the crank angle sensor is placed further in front of the engine. Before you head out and buy a replacement crank sensor, you should check the operation by using your digital multimeter first.

Common causes when your Focus won’t start

There are some rare cases when your Focus won’t start due to battery voltage. This is because your crank angle sensor does not have the right power to provide the resistance required to operate. There’s also a chance that your stored OBDII DTC trouble code is caused by a lack of power from your battery.

So make sure to have your battery and alternator checked before testing the crank sensor. If your alternator and battery check out in your Ford, then we can begin testing the crank sensor directly.

How To Test your Focus crank sensor

Once you have access to your crank sensor, you will need to turn the dial of your multimeter to read resistance or OHMS Ω. This part is mounted behind the crankshaft pulley otherwise known as your harmonic balancer. If you see your crank reluctor wheel behind the crankshaft plate, inspect it for any damage or bent fins.


Pierce the wires coming out of this two pin crank sensor and you’ll be measuring the voltage directly. You can do this one of two ways, although one of the methods is safer than the other.

Start your Focus – While you have your vehicle in PARK or neutral with your parking brake engaged, have a friend start your vehicle. Keep your hands, clothing and tools clear of your engine and pulleys. Make sure your multimeter and wires are free and clear of your crank pulley or belts.

Manually turn your engine – Using a half inch ratchet, manually rotate your engine by turning the crankshaft pulley bolt. Of course this must be done with your Focus ignition turned to the “ON” position. It’s easier to do when you unplug your spark plug wires and remove your spark plugs.

Either way you want to test your Ford, there should be only one result. The sensor should send a signal that jumps from .5 volts to 1 volt as your engine rotates. It should never read between these two signals or miss any gaps in signal. When there’s no signal at these wires or a constant 5 volt power signal, it’s proof that your Focus crankshaft position sensor has failed.

Replace your Ford Focus Crank Sensor

Remove the bolt that secures this sensor through the front of the engine. Take out your failed crankshaft sensor, and install your new crankshaft position sensor. You will of course need a scan tool to clear any OBDII DTC Focus trouble codes like P0335.

Have any questions about this DIY testing guide for your Focus crank sensor? Leave us a comment below and let us know!