How to check the camshaft sensor
Camshaft position sensor (DPRV) serve for, to determine the angular positions of the timing in relation to the position of the crankshaft. Signals from the specified sensor are fed to the computer by the engine, which corrects fuel injection and ignition. The DPRV also works in conjunction with a crankshaft speed sensor.
Sensor malfunctions on gasoline units, which are manifested in the absence of impulse on the control unit, often do not allow to start the car engine. In diesel engines, starting can be difficult, but possible. The diesel engine will run and even restart after stopping, since the ECU receives pulses from the crankshaft speed sensor in parallel.
We also recommend reading the article about the Hall sensor device. In this article you will learn about the design, principles of operation of devices and their application on cars.
Purpose of the camshaft position sensor
The Hall effect is the basis of the sensor for determining the position of the camshaft. For this reason, DPRV is also called a Hall sensor. The change of the magnetic field in such a sensor is carried out at that moment, when the magnetic gap is closed.
The specified gap is closed by means of a special steel tooth. Such a tooth (benchmark) can be located on the camshaft gear. Another location of this element is the setting disk, which is mounted on the shaft.
When the tooth passes next to the distribution position sensor, voltage appears in the sensor and a signal is generated. The specified signal is received by the ECU.
The faster or slower the camshaft rotates, the greater or lesser the frequency of pulses from the sensor for a certain period of time. The control unit is based on these signals, determining the position of the piston in the first cylinder.
This position should be understood as the location of the piston in the TDC (top dead center at the end of the compression stroke). This solution allows for timely fuel injection and subsequent sparking by a spark plug to ignite the working mixture..
Motors with variable valve timing system can be equipped with Hall sensors on the intake camshafts, and on release. In this case, the DPRV controls the specified system.
We also recommend reading the article on gas distribution phase change systems. In this article you will learn about the device and the principles of these systems.
Camshaft sensor on diesel engine
On the diesel engine the sensor of position of a camshaft works differently in comparison with petrol analogue. Pulses from the sensor fix the position of the piston in TDC not in the 1st cylinder, and all. This solution allows to achieve the most accurate determination of the position of the camshaft relative to the crankshaft. In the diesel DPRV is responsible for efficiency of start and stability of work of the power unit of this type on various operating modes.
In diesel, certain design changes are present on a given disk. Teeth on the specified element are made for each cylinder of the internal combustion engine and are installed at a certain distance. As an example, consider a diesel engine, which has 4 cylinders. In such a motor sets the disk has 7 teeth (4 tooth core, located at an angle to 90 degrees relative to each other). There are also additional ones 3 tooth, allowing to identify cylinders separately. These teeth are located at a certain distance from the main, to accurately determine the position of the piston in each individual cylinder.
self-check
A common malfunction of electron injection engines is sensor malfunctions camshaft position. In the list of signs, indicating sensor problems, note:
- difficult start;
- unstable engine operation;
- the engine is shaking, works intermittently;
- possible fire "check" on the dashboard;
- The first step is to identify the landing nest DPRV, which is installed in the area of the cylinder head. A special seal ring must be found at the installation site. The specified ring must be inspected, as violation of its integrity and other deformations can lead to malfunctions of the sensor.
- Additionally, you will need to inspect the sensor housing itself, as well as a toothed rotor. The presence of damage or the presence of metal shavings also indicate a breakdown of the sensor.
To test the camshaft position sensor yourself, use a tester / multimeter. The ignition must be switched off before testing. Then you can start disconnecting the wires from the device. Most wiring is secured with standard connectors. Disconnection is carried out by pressing the special latch-latch pads.
- Next you need to study the connector itself. Contacts must be present on this connector: positive contact, negative "mass", contact for signal transmission.
- Then you need to turn on the ignition, then the voltmeter measures the voltage at the positive contact of the camshaft position sensor. The weight of the tester must be connected to the weight of the engine. This voltage measurement should be similar to the voltage at the terminals of the battery. In the case of deviations in the voltage readings compared to the power supply, a conclusion can be drawn, that there are faults in the electrical circuit of the camshaft position sensor.
- Similarly, the voltage measurement on the "mass" of the sensor is measured. The voltage at the specified contact must be zero.
- Then you need to connect the positive and negative wires of the sensor. The middle contact of the sensor is connected via a tester. It turns out, one voltmeter probe is attached to the signal output of the sensor, and the other is fed to the input in the control system. To solve this problem, the signal wire is often cut, and the multimeter probe is attached to open wires.
- Then the engine scrolls the starter. The operating sensor will show the voltage, which can range from 0.4 to 5 volt. Deviations from these values indicate the need to replace the DPRV.
To replace the camshaft position sensor yourself, you need to disconnect the drive from it, remove the fasteners and remove the device from the seat. The connection of a working element is carried out in the reverse order.
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