Checking the camshaft sensor

Checking the camshaft sensor (DPRV) allows not only to verify its performance, but also to make sure that in the internal combustion engine with phased (sequential) injection, fuel is supplied in exactly the right sequence. Another name for the device is a phase sensor (it is often used by owners of domestic VAZs). Checking can be done with a multimeter, included in the voltmeter mode, and / or an oscilloscope. Checking the camshaft position sensor is simple in nature, and even a novice motorist can handle it.

What is a camshaft sensor

Before moving on to the question of checking the camshaft position sensor, you need to find out what kind of device it is, what it is for, and on what principle it works. This will help clarify the details of the verification in the future.

The camshaft sensor is a device that captures the angular position of a specified shaft at a specific point in time. The information received with its help is transmitted to the ICE electronic control unit (ECU), and on its basis this control gives commands for fuel injection and ignition of the air-fuel mixture in each cylinder at a specific point in time.

The operation of the camshaft position sensor is based on the Hall effect. So, it is on the camshaft that there is a metal tooth, which, during the rotation of the shaft, changes the magnetic field in the adjacent sensor. This tooth is called a rapper. The sensor detects a change in the magnetic field, which is converted into an electrical signal of a small voltage. This signal is sent to the electronic control unit.

In reality, the camshaft position sensor detects only one of its positions, corresponding to the position of the piston of the first cylinder at top dead center. further phased fuel injection is performed in the sequence of the cylinders. Usually it is a 1-3-4-2 system.

Camshaft position sensors have been installed on engines with split (phased) fuel injection since about 2005.

If the camshaft sensor fails (the electronic control unit receives incorrect information from it or does not receive it at all), then the transition to emergency mode is programmed. It involves the use of pairwise-parallel (group) supply of fuel to the internal combustion engine. This leads to two negative consequences:

1. A slight loss of ICE power, especially when driving in critical modes (acceleration, driving under load).
2. An increase in fuel consumption by approximately 10 ... 20% (depending on the power of the internal combustion engine, its design features, as well as operating conditions).

As for diesel engines, the camshaft position sensors are similar, but there is one difference. It lies in the fact that the sensor captures the position of not only the first cylinder, but all. This is done due to the fact that the master disk has a separate tooth for each cylinder.

So, if the sensor fails, it is worth diagnosing it as soon as possible and, if necessary, replacing it.

Signs of breakage DPRV

There are several typical signs by which it can be argued that the camshaft position sensor is out of order. It is immediately necessary to clarify that the symptoms listed below may indicate completely different malfunctions. Therefore, it is worth making additional diagnostics. So, the signs of a breakdown of the DPRV:

• Problems with starting the internal combustion engine, and under any conditions - “cold”, “hot” and in other modes. Usually this is expressed in the fact that you have to turn the starter longer.
• Unstable operation of the internal combustion engine, “floating” working and idle revolutions of the internal combustion engine.
• "Dips" in the movement of the car, when you press the accelerator pedal, it does not respond immediately, the dynamic characteristics of the car are lost (it accelerates weakly, does not pull, especially when loaded and when driving uphill).
• When the accelerator pedal is released, the internal combustion engine stalls.
• Increased fuel consumption (by 10 ... 20%).
• The warning light on the Check Engine dashboard is activated. it is necessary to make additional diagnostics using an electronic scanner (for example, an ELM 327 device or its equivalent). At the same time, typical errors regarding the operation of the sensor have the numbers P0340, P0342, P0343.

In fact, the camshaft position sensor is a fairly simple and reliable device, so it rarely fails. More often, its wiring is damaged - the wires are frayed, the insulation on them is damaged, the so-called “chip”, the place where the sensor is connected to the machine circuit, fails.

However, for cars running on gasoline, the problems described above are not so clearly expressed. But a failed camshaft position sensor will cause many problems for owners of cars equipped with gas-balloon equipment, namely the fourth generation. The breakdowns and problems described above can appear on such machines "in all their glory." Therefore, owners of cars equipped with HBO are strongly recommended to diagnose and replace the sensor as soon as possible if it is suspected of a breakdown.

Location of the DPRV on the internal combustion engine

To perform a camshaft position sensor test, you need to know where it is located. usually, on eight-valve internal combustion engines, the DPRV is usually mounted at the end of the cylinder head. On sixteen-valve engines, it is also mounted on the cylinder head, usually in close proximity to the first cylinder.

As for the popular domestic VAZ cars, their owners call such nodes phase sensors. Their location in these motors is similar. So, on eight-valve internal combustion engines, the sensor is located on the left side of the cylinder head (when viewed in the direction of the car). On sixteen-valve - on the right front of the internal combustion engine. In the latter case, it is the sensor that is not visually visible, its location can only be estimated by the signal and power wires suitable for it. The VAZ 2114 phase sensor is fixed in close proximity to the air filter, near the cylinder head.

Methods for checking the camshaft sensor

Before testing the sensor with a multimeter or other electronic devices, it is necessary to check its mechanical integrity. namely, it is installed in a housing with an o-ring to secure it securely. We need to check its condition. it will also be useful to check the integrity of the sensor housing, the presence of cracks or other damage on it. It is advisable to check the drive disk as well, whether the teeth are damaged, whether there are metal chips on the sensor housing or near it.

On the Internet, you can find information that supposedly the DPRV can be used to identify its performance by simply checking its magnetic properties. namely, bring a small metal part to its end (the working sensitive part), which should “stick” to the sensor. In reality it's not, and a non-working DPRV may or may not have magnetic properties. Accordingly, verification must be performed by other methods.

There are two basic ways to check the camshaft position sensor - using an electronic multimeter and using an oscilloscope. The first method is simpler and faster, but the second is more accurate and provides more diagnostic information.

Checking the camshaft sensor with a multimeter

To check the DPRV, dismantling is necessary. This is easy to do, you just need to disconnect the contact group of wires from it and unscrew the mounting bolt. also, to check, you will need a small metal object (made of black metal, in order for it to be magnetized).

Connection diagram for checking the phase sensor 21110-3706040

Connection diagram for checking the phase sensor 21120-3706040

The algorithm for performing a sensor check with a multimeter is as follows:

1. Take a multimeter and switch it to the DC voltage measurement mode in the range of up to 20 V (depends on the specific multimeter model).
2. Disconnect the "chip" from the sensor by snapping off the latch.
3. Remove the sensor from its seat.
4. On the "chip" of the sensor 21110-3706040 of the VAZ car (and on many others), contact "A" corresponds to the mass, contact "C" is the positive wire, comes from the control relay, contact "B" is the signal wire (middle). At the 21120-3706040 sensor chip, contact "A" corresponds to mass, contact "B" is a positive wire from the control relay, contact "C" is a signal wire.
5. Check the presence of power on the chips. To do this, you need to turn on the ignition on the car (but do not start the internal combustion engine) and do this with a multimeter. If there is no power on the chips, then you need to look for the cause. This may be faulty wiring (damage to insulation, broken wires), failure of the control relay, a “glitch” of the electronic control system (ECU).
6. next, you need to connect the sensors for testing according to the diagrams shown in the figure.
7. Apply a voltage of 13,5 ± 0,5 V to the sensor (although less is allowed, for example, 12 ... 12,5 Volts from the battery).
8. If, when power is applied to the sensor, the voltmeter detects the absence of voltage on the sensor, then this signals either a breakdown of the sensor itself, the test can be completed and prepare to replace the sensor with a new one.
9. Measure the voltage between the positive and signal contacts. It must be equal to at least 90% of the supply voltage (that is, if the supply voltage is 12 Volts, then the voltage at the signal contact must be at least 10,8 Volts).
10. Bring a metal object prepared in advance to the end of the sensor (its signal part). Re-measure the voltage at the signal contact. It should be no more than 0,4 volts. Remove the plate - the voltage value should be restored to 90 ... 100% of the supply. If there are any deviations during the verification process, it means that the sensor is out of order and must be replaced.

Please note that it is advisable to check not only sensors already installed on the internal combustion engine, but also newly purchased ones, since there is always a risk of buying a defective product.

Checking the DPRV with an oscilloscope

An electronic oscilloscope helps to understand how the camshaft position sensor works, and whether it produces pulses at all. Usually they use the so-called electronic oscilloscope, that is, just a simulator program installed on a laptop or other similar device. you need to connect to the camshaft sensor and take an oscillogram from it. Ideally, there should be a flat comb pattern with a single outlier peak that corresponds to the rapper passing through the transducer. If the waveform has a different shape, an additional check is needed.

When diagnosing a Nissan camshaft sensor (namely, Nissan Almera) with an oscilloscope, the shape of the waveform will be different. It will not be smooth, but in the form of 3 pulses, then a space, then 4 pulses - a space, 2 pulses - a space and one pulse - a space. For the engine of this automaker, this feature is the norm.

Replacing the PB position sensor

If during the test it turned out that it was the camshaft position sensor that failed, then it must be replaced. usually, these units are non-repairable, since their body is soldered, and it is impossible to disassemble it. The sensor is inexpensive, and the replacement procedure is simple, and even a novice motorist can handle it.

The sensor replacement algorithm is as follows:

1. With the engine off, disconnect the negative terminal from the battery.
2. Disconnect the “chip” from the camshaft position sensor (as when checking).
3. Depending on the car model, it is necessary to dismantle the parts that prevent access to the sensor. For example, on modern cars like Lada Vesta, you need to remove the bracket for auxiliary units.
4. Using a wrench, unscrew one or two mounting bolts, depending on the type of fastening. The size of the wrench can be different, usually for VAZs this is a 10 mm wrench.
5. After dismantling the mount, you need to similarly remove the sensor from its seat.
6. Installation of a new sensor is carried out in reverse order.
7. Connect the negative terminal to the battery.

When buying a new camshaft position sensor, you need to pay attention to the condition of its sealing ring. It is usually sold separately. It is advisable to change the sealing ring when changing the sensor, since over time it wears out and loses its elasticity. You can use the old ring only in case of emergency, when it is not possible to buy a new one.

Hack and predictor Aviator

The camshaft position sensor is a simple but important device in the internal combustion engine, and the normal functioning of the internal combustion engine depends on its operation. Therefore, when identifying signs of its failure, it is desirable to carry out appropriate diagnostic procedures as soon as possible. They are simple, and even a beginner with no experience, a car enthusiast can handle them. Likewise with its replacement. The price of a phase sensor for VAZ vehicles as of the winter of 2019 is about 400 rubles.