How to Test Crankshaft Position Sensor with a Multimeter

Is your car not starting? There might be a problem with your CKP sensor. The crank sensor notifies the engine control unit (ECU) when the spark plugs should be fired. Also, it controls the timing and volume of fuel injection into the combustion chamber of a vehicle.

In general, there are two types of CKP sensors, inductive and hall-effect. You can test the inductive type sensor with a multimeter through the steps below:

Unplug the CKPS’s electrical connector and set your DMM to low-range DC voltage settings.
Stop your engine from starting, then turn the ignition key to its “On” position.
Connect your DMM’s black lead to the ground and connect the red lead to each sensor wire.
Set your DMM to a low-range AC voltage scale and connect the sensor pins to your meter leads.
While watching the meter’s readout, have an assistant crank the engine for a few seconds.

Usually, a common issue is that the crank sensor can be damaged, necessitating a test using a measurement tool such as a multimeter. So, in this article, I’ll show you how to test the crankshaft position sensor with a multimeter.

Bad CKP Sensor Symptoms

A failed or bad CKP might cause the following symptoms:

Difficult to start
No-start situation with a cranked engine
Starting and stalling condition
Irregular stalling
Idle time is rough.
Hesitation
Sluggish acceleration
Fuel use has increased
Misfiring
A check engine indicator is on
The tachometer may function incorrectly or not at all

Malfunctions in other systems, such as the fuel or ignition systems, might cause some of the same symptoms. As a result, a crankshaft position sensor test is critical for a more accurate diagnosis. With a multimeter, you can test your CKP regardless of whether it’s an inductive or hall effect sensor.

Crankshaft Position Sensor Test (Steps)

So, let’s get into our main question how do you test a crankshaft sensor with a multimeter?

We layout the steps below:

Testing a 2-Wire or Inductive Type CKP Sensor

Multimeter and Inductive Type CKP Sensor — Video | Ratchets And Wrenches

Unplug the electrical connector for the CKP sensor.
Set the digital multimeter to DC voltage settings using a low range.
Toggle the ignition key to its “On” position without starting your engine.
Connect your multimeter’s black lead to the ground. It can be a clean engine surface, a metal bracket, or the battery’s negative (-) post.
Connect your multimeter’s red lead to each sensor wire on the disconnected harness connector. If one of the cables produces approximately 1.5 volts, the sensor is not receiving a reference voltage and must be repaired.
To avoid the engine from starting, you can disable the fuel system by disconnecting the fuel pump fuse or relay. Alternatively, you can disconnect the ignition cable between the distributor and ignition coil. (1, 2)
Choose a low range on the AC voltage scale on your digital multimeter.
Connect the sensor pins to your meter leads. During this test, ensure the meter lead wires are kept away from moving engine parts.
While watching the meter’s readout, have an assistant crank the engine for a few seconds.

Your sensor should generate a voltage pulsing signal. Replace the sensor if no voltage pulses are visible. If your multimeter is capable of frequency (Hz) measurements, you can use this option in the same method on checking for an AC signal. Then, compare your findings to the manufacturer’s guidelines. With that, I recommend consulting your vehicle’s repair manual for assistance.

You can also examine the resistance of your inductive CKP sensor by doing the following steps:

Set your digital multimeter to Ohms.
Unplug the electrical connector of your CKP.
One DMM lead should then be connected to one of the sensor pins, while the other should be connected to the other sensor pin.
Turn your multimeter on.

Depending on the model of your vehicle, the reading should show a resistance value of between 200 and 2000 ohms.
Compare your findings to the specs provided by the manufacturer. You can find it in your vehicle’s repair manual. Replace the sensor if it is not up to specification.
If the result shows infinite resistance, your sensor has an open in the circuit.
If the result shows zero Ohms, your sensor has a short circuit.

Testing a 3-Wire or Hall Effect Type CKP Sensor

Hall Effect Type CKP Sensor testing with Multimeter — Video | Ratchets And Wrenches

During the test, prevent the engine from starting by disconnecting the fuel pump fuse or relay.

If your engine has a distributor, unhook the central ignition cable and use a jumper wire to connect it to the engine.

Unplug the electrical connector of your CKP.
Set your digital multimeter to DC volts with a 20-volt range.
Connect your multimeter’s black lead to the harness connector’s black wire.
Connect your multimeter’s red lead to the harness connector’s red (power) wire.

If the CKP sensor uses various colored wires, you might need to verify the wiring schematic for your specific model to identify the power, ground, and signal wires.

Toggle the ignition key to its “On” position.
The reading should be between 5 and 13 volts. In your vehicle’s repair manual, you can find the reference voltage value for your specific model.

Check the connector and wire for damage or a loose termination if your reference voltage is less than expected or zero. Also, examine your vehicle’s computer if necessary.

Turn off the ignition, then reconnect the CKP sensor to the harness connector.
Set your multimeter to read millivolts through a low DC voltage preset.
Connect your multimeter’s black lead to the battery’s negative terminal.
Use the red lead to back probe the black, ground wire at the CKP sensor or harness connector.
For a few seconds, have an assistant in cranking the engine. About 200mv to 300mv should be registered on your DMM.
Connect your multimeter’s red lead to the green (signal) wire on the harness connection or CKP sensor.
Then for a few seconds, crank the engine. You should see roughly 300mv on your meter. That is the average voltage value that the CKP sensor will produce.

mechanic in his gloves holding crankshaft

Depending on your system, you might be able to detect a CKP signal with your multimeter if it can read Duty Cycle signals. You need to back probe the sensor’s signal wire and connect the DMM’s black lead to the ground.

Set your DMM to Duty Cycle and have someone else start the engine for you.
The sensor may be defective if the CKP fails to give a duty cycle signal.

Also, don’t check the resistance of a Hall effect CKP sensor unless it is specified in your car repair manual. It is because the induced voltage may damage internal components.

FAQs

CKP Sensor: What Exactly Does It Do?

In general, the CKP keeps an eye on piston movement and the crankshaft’s position. It also assists the computer in keeping track of engine misfires and speed. With that data, the computer adjusts the ignition timing and fuel injection.

However, the crankshaft sensor is subjected to heat and vibration during engine operation. It wears on the sensor, or its circuit may eventually fail. A diagnostic trouble code (DTC) referring to a problem with the CKP sensor, or the sensor’s circuit, may be stored in the car’s computer, as it is with other emission-related sensors:

– P0315
– P0335-P0339
– P0385-P0389

You may also encounter the following code if your engine has a camshaft position (CMP) sensor:

– P0016-P0019

What are the two types of CKP sensors?

CKP sensors come in two varieties, which are used in the majority of automobiles nowadays:

Inductive (Magnetic) CKP Sensor
It has one or two wires.
It generates its signal of AC voltage.

Hall-Effect CKP Sensor
It has three to four wires.
It produces a square wave digital signal.
It needs an external power source and ground to make the signal.

Where is the CKP Sensor Located?

Depending on your vehicle’s make and model, you can find the CKP sensor in the following locations:

– In the front or timing cover of the engine, near the crankshaft pulley, or behind the harmonic balancer.
– Around the center of the engine block.
– Under your vehicle’s starter motor.
– On the back of the engine, near the flywheel ring gear, in the bell housing of the transaxle.

If necessary, I recommend consulting your vehicle’s service manual to find the sensor for your model.

What if my CKP passes the test?

Even if your engine exhibits the symptoms of a faulty CKP, this does not always imply that your sensor, wiring, or connector is malfunctioning. The issue may be caused by the components with which it communicates.

Depending on your model’s specific design, there could be an issue with the ignition control module (ICM) or, less commonly, the PCM itself. Consult your owner’s handbook if necessary. You could also check the camshaft position sensor if the ignition system produces a spark, but the fuel injectors are not working.

Take a look at some of our related articles below.

References
(1) fuel system – https://www.sciencedirect.com/topics/engineering/fuel-system
(2) coil – https://www.britannica.com/technology/coil

Video Reference