How to Test a 3 Wire Crank Sensor with a Multimeter

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The crank sensors are part of the car’s engine and in charge of making the rotation. A faulty sensor could keep your vehicle from making a move. It would create a noise, but it would not start. You may also encounter a loss of power in the engine, misfiring, and there might be no spark while you start the engine. 

The crankshaft position sensor measures the rotation speed and the exact position of the engine crankshaft. Without it, the engine would not start. 

In other vehicles, the sensor is installed near the main pulley. In others, the sensors could be installed at the transmission bell housing or within the engine cylinder block. Technically speaking, the crankshaft position sensor is short to CKP. 

3-wire crank sensor meaning 

In a nutshell, a crank sensor monitors crankshaft position and piston movement. It also helps the computer monitor engine misfires as well as engine speed. The computer utilizes that information to adjust fuel injection and ignition timing.

Nonetheless, a crank sensor endures vibration and heat during engine operation. Later on, that takes its toll, and the circuit or the sensor might malfunction. The vehicle’s computer might store a diagnostic trouble code as with other emission-related sensors pointing to an issue with the crank sensor or the sensor’s circuit. Does your sensor use a CMP sensor? Then you can also see other related codes.

That’s why you should troubleshoot your 3-wire crank sensor whenever you suspect issues to ensure the problem is with the sensor itself or one of the parts within the system it works with.  

Four signs you need to replace your crank sensors

Remember that a malfunctioning crank sensor could cause your vehicle to “die” or render it unable to start, although the engine might normally be running. A crank sensor sends information to the computer of your car, referencing how to switch the engine is running, and essentially, the position of the cylinder and the crankshaft. 

That sensor is instrumental in regulating the timing and ignition of the engine and even fuel injection operation. 

Below are the common issues you may encounter that will tell you to have a bad or malfunctioning crank sensor. 

  1. Damaged timing belt 

The belt could get wrapped around your crankshaft and destroy many tiny sensors and parts. The crank sensor might have been hit by the timing belt when it broke. That could cause damage to the sensor and the wiring harness.

The sensor could still be damaged although you have had the belt changed, and your car may crank but fail to remain started for several minutes. 

  1. Backfiring and stalling

This is another problem telling you that you have a malfunctioning sensor. In this scenario, your car won’t run; still, the engine would turn off after a few moments. Keep in mind that the misfiring will happen the same way. The engine will shut off enduringly if you keep overlooking this symptom.

  1. Missing crank signals

Do you have a totally failed crank sensor? Then your computer can’t longer measure engine speed. When that happens, the fuel system and ignition system shut down, which causes the engine to crank and don’t start or stall when the engine is running. 

  1. Intermittent crank signal 

Does your crank sensor deliver a signal, which is intermittent? Perhaps it shows the wrong crank position. Then that can cause backfiring, rough idling, and even loss of power. 

How Do You Test a Crank Sensor with a Multimeter? 

As you may already realize, the camshaft position sensor might fail because of wear and tear. Thus, the signs discussed above will enable you to understand if you need to fix it or change any parts.

Take note that testing the crank sensors is the way out once you understand the best category. What we mean by category is whether it’s a 3-type wire or a 2-type wire. You could check it out by checking the connector. Determine if it has two or three wires. 

In today’s guide, our goal is to check a 3-wire crank sensor. We can do that by using a digital multimeter. Follow the steps below, so you are guided. 

  1. For the first step, make sure you determine three of the wires for signal wires, ground, and power. You can utilize your car repair manual for this process to help you determine the three wires effortlessly. 
  1. Grab your digital multimeter and set it to DC volt settings. Likewise, turn the ignition key on without turning your car’s engine. 
  1. Grab the black probe of your digital multimeter and touch the ground. Attach the red probe to the power wire. The reading will appear, and it should match along with the specifications specified in your manufacturer’s manual. 
  1. Start your engine. Get the signal wire to touch along with the red probe and the ground probe wire to the black probe. Are your readings lower than the designated specification? Then it suggests you have a bad sensor, and you should replace it immediately.

Replacing a bad crank sensor is not very costly. The component typically costs from $35 to $115, not to mention you need to spend $55 to $150 more for the labor. It would be best if you used an OEM part in this case.

Keep in mind that it is relatively simple to replace in most cars, even though the sensor could often be challenging to get rid of because of corrosion. You can watch some YouTube videos to get a further understanding of this topic. 

When changing a crank sensor, you should confirm the right gap between the sensor and the reluctor ring teeth. 

Final Thoughts

Do you suspect you have a bad crank sensor? Then it would help if you don’t drive your car. As an alternative, use the steps above and start your 3-wire crank sensor with the help of a digital multimeter. If you find any bad symptoms, make sure you bring your vehicle to your car center or get in touch to your nearest service provider right away.

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