How to test crankshaft position sensor with a multimeter
1.
Depending on the make and model of your particular vehicle, a defective or poor CKP may cause one or more of the following symptoms:
Severe start-start, non-start conditionStart and stop conditionIdle conditionIncreased fuel consumptionIgnosion faultCheck engine light
But problems in other systems (e.g. fuel or ignition systems) can also cause some of the same symptoms. It is therefore important to test CKP to better diagnose the problem.
Although it is recommended to test a CKP sensor with an oscilloscope, this is not a common tool for many car owners or DIY enthusiasts. You can still check the sensor with a digital multimeter (DMM), regardless of whether your engine uses an inductive or Hall effect sensor.
This is what you will do here with the help of this guide. Note, however, that you will need the electrical values for your specific make and model of car to locate the sensor, identify the cables and replace them if necessary.
You will find this information in your car’s repair manual. If you do not already have this manual, you can purchase a relatively inexpensive post-purchase version from Amazon. Haynes manuals come with many pictures and step-by-step maintenance, repair and troubleshooting projects for many systems in your vehicle. This way you will get your small investment back in a short time.
The CKP sensor controls the position of the crankshaft and the engine speed. The | source
1. What is a CKP sensor used for?
In general the CKP controls the movement of the piston and the position of the crankshaft. It also helps the computer to control engine failure and engine speed. The computer uses this information to adjust the ignition timing and fuel injection.
However, a CKP sensor can withstand the heat and vibration during engine operation. This eventually takes its toll and the sensor or its circuit may fail.
As with other emission-related sensors, the vehicle’s computer can store a Diagnostic Trouble Code (DTC) that signals a problem with the CKP sensor or sensor circuitry, such as
P0315P0335-P0339P0385-P0389
If your engine uses a camshaft position sensor (CMP), you can also see a corresponding code:
P0016-P0019
Therefore, if you suspect a CKP problem, it is important to troubleshoot to ensure that the problem is related to the sensor, circuit, or one of the system components it is working with.
The following sections will help you test your CKP sensor with a digital multimeter (DMM) only, regardless of whether your motor uses an inductive or Hall effect sensor.
2. how to tell whether you have an inductive or Hall effect CKP sensor
Basically, most vehicles on the road today use one of two types of CKP sensors.
Inductive (magnetic) CKP sensor:
Can have one or two wires Mounted in front of a rotor or steering wheel Generates its own AC signal
Hall effect sensor CKP:
Can have three or four wires, is mounted in front of a rotor or gear wheel, generates a digital signal (square wave), requires an external power source and a ground to generate the signal.
You can use a digital multimeter to test the CKP sensor. The | source
3. Troubleshooting a CKP sensor
Many problems with the CKP sensor can be in the wiring harness or in the sensor connector. Therefore, be sure to check them carefully before you start troubleshooting the sensor. But first the sensor must be located.
Depending on the make and model of your car, you may find the CKP sensor:
mounted on a front engine cover or timing case cover, near the crankshaft pulley or behind the harmonic balancer.somewhere in the middle of the engine block.under the starter.at the rear of the engine, in the transaxle bell near the flywheel rim.
If necessary, consult your vehicle’s manual to find the sensor on your specific model.
Checking the wiring and sensor
Often a sensor that fails or does not work comes from a faulty cable or connector. Perform a visual inspection of the wiring harness and connectors between the sensor and the PCM or power module.
Check wires for damageCheck loose wiresCheck loose sensor mounting screwsCheck electrical connector for damageCheck sensor itself for signs of damageCheck air gap between sensor tip and rotor, if necessary Refer to your vehicle’s repair manual for specifications. Remove the sensor and check whether metal chips or shavings are attached to the sensor magnet tip.
If your vehicle uses a distributor, disable the ignition system to start the engine. The | source
Testing of an inductive sensor type CKP
The following steps give you an example of how to test an inductive sensor of type CKP.
However, be sure to consult your vehicle’s repair manual for electrical values and possibly a recommended method of testing the CKP sensor on your specific model.
Disconnect the electrical plug from the CKP sensor and set your digital multimeter to the DC voltage scale with a low range. This may be a clean surface on the engine, a metal bracket, or the negative (-) terminal of the battery. One of the wires should produce about 1.5 volts, otherwise the sensor will not receive a reference voltage and will need to be repaired.
To prevent the engine from starting:
Deactivate the fuel system by removing the fuse or relay from the fuel pump or by disconnecting the ignition cable between the ignition coil and the distributor.
If necessary, consult your vehicle’s repair manual. This will prevent the engine from starting.
Set your digital voltmeter to a low range on the AC voltage scale. Make sure that the test leads are away from the moving parts of the engine during this test. Have an assistant start the motor for a few seconds while you observe the meter reading.
The sensor should generate a pulsating voltage signal. If you do not see any voltage pulses, replace the sensor. Compare your results with the manufacturer’s specifications. Refer to the repair manual of your vehicle.
You can check the resistance of your inductive CKP sensor:
Set your DMM to the ohmic scale.
Unplug the electrical CKP connector.
Connect one DMM cable to one of the sensor pins and the other DMM cable to the other sensor pin. It does not matter which one.
Turn on your DMM.
The reading should indicate a resistance value, usually between 200 and 2000 ohms, depending on the model of your particular vehicle. Refer to your vehicle’s repair manual for the specification. If the reading is infinitely resistive, the sensor has an open circuit; if the reading is zero ohms, the sensor has a short circuit.
Test the resistance of a CKP
Do not test the resistance on a Hall effect sensor of type CKP. Induced voltage can affect the operation of a good sensor.
If you disconnect the ignition cable from the distributor, ground the engine with a jumper cable. The | source
Testing of a Hall Effect Sensor Type CKP
The best way to test a Hall effect sensor is with an oscilloscope. But not many do-it-yourselfers own one. You can still use a DMM to test this type of CKP sensor on your car.
Although you won’t see the high and low voltage graph and frequency you see on an oscilloscope reading, you’ll get the average voltage from the sensor, which will give you an idea of how it works.
Remove the fuse or relay from the fuel pump to prevent the engine from starting during this test.
If your engine uses a distributor, you can disconnect the middle ignition cable and connect it to the engine with a jumper cable. If necessary, consult your car’s repair manual. Disconnect the electrical plug from the CKP sensor. Set your DMM to DC voltage and the 20 volt range. Touch the black DMM cable to the black wire of the wiring harness connector.
Touch the red DMM cable with the red wire (power) to the wire harness connector.
You may need to check the wiring diagram for your specific model if the CKP sensor uses different colored wires to identify the ground, power, and signal lines. Turn off the ignition and plug the CKP sensor back into the wiring harness connector. Touch the black DMM wire with the negative battery, then use the red measuring wire to sense the black ground wire back into the wiring harness connector or the CKP sensor. Your DMM should register approximately 200mv to 300mv. Now touch the red wire from the DMM to the green wire (signal) at the wire harness connector or CKP sensor.
Start the engine for a few seconds. Your meter should register about 300mv. This is an average voltage value of the signal generated by the CKP sensor.
If necessary, compare your results with the information in your car’s repair manual.
Although not as often, the computer in your car may be at fault. The | Source
4. What happens if my CKP passes the test?
Even if your engine has the symptoms of a poor CKP, it does not necessarily mean that your sensor, wiring or connector is damaged. The problem could be in the components it communicates with.
There may be a problem with the ignition control module (ICM) or even, though not as often, with the PCM itself, depending on the particular configuration of your model. If necessary, consult your vehicle’s repair manual.
5. replacing the CKP sensor
In general, replacing a CKP sensor is a fairly simple process. However, on some models, you may need to remove one or more components to gain access to the sensor. Refer to your vehicle repair manual.
Make sure the engine is cold and the ignition switch is in the off position. Disconnect the negative (black) battery terminal. On some models, you must lift the front of the vehicle and secure it in the socket holders to gain access to the sensor. Disconnect the electrical plug from the CKP sensor. This will help place the sensor correctly, help the sensor generate the correct signal, and prevent oil leakage. Install the new sensor and tighten the mounting screws.
For some engines, you must set the correct distance for the sensor. Follow the instructions supplied with your new CKP sensor or your vehicle’s repair manual. The following video gives you an idea of how to replace a crank position sensor.
how to test ignition control module with multimeter