The crankshaft of a car is used to convert the translational motion of the pistons into rotational motion. On technical equipment with an electronic engine control system, a crankshaft position sensor (hereinafter referred to as CPPS) is installed. The controller is necessary to synchronize the ignition angle and the fuel system.
In the event of a malfunction of the equipment, a yellow indicator on the dashboard indicates the presence of a breakdown. The engine is unstable, idle speed is systematically reduced, power drops, and fuel consumption increases.
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Cars with injection, which is the Lada 4*4 or Niva, have many different sensors that are responsible for the operation of the entire car. The failure of one of them seriously affects the operation of the entire power plant. As a rule, a breakdown of the sensor leads to the lighting of the lamp on the “CheckEngine” dashboard, but the sensors have one problem: they do not fail immediately, but gradually and can give incorrect readings to the engine control unit, which will certainly lead to unstable operation of the internal combustion engine.
As a rule, failure of the sensor does not stop the car completely, but only puts the internal combustion engine into emergency mode. In this mode, the car can safely drive to the nearest service station, where it will be put in order.
But, there is one sensor that is responsible for reading and the state of the crankshaft position (CPCP); a breakdown of this sensor completely stops the internal combustion engine and makes it impossible to start until the cause is eliminated.
It should be noted that checking the sensor and signs of malfunction are similar to the Chevrolet Niva.
In this article we will talk specifically about the DPKV, namely its location, signs of malfunction, methods of checking and replacing.
Where is the crankshaft position sensor located?
The induction type crankshaft position sensor is installed next to a special disk located in conjunction with the crankshaft drive pulley.
The special disk is called a reference or master disk. Together with it, it ensures angular synchronization of the operation of the control unit. Skipping two teeth out of 60 on the disk allows the system to determine the TDC of the 1st or 4th cylinder. The 19th tooth after skipping should face the DPKV rod, and the mark on the camshaft should be against the bent reflector bracket. The gap between the sensor and the top of the disc tooth is in the range of 0.8-1.0 mm. The sensor winding resistance is 880-900 Ohms. To reduce noise levels, the crankshaft sensor conductor is shielded.
After turning on the ignition, the control program of the unit is in the waiting mode for the synchronization pulse signal from the crankshaft position sensor. When the crankshaft rotates, the sync pulse signal arrives instantly to the control unit, which, in accordance with their frequency, switches the electrical circuit of the injectors and the ignition coil channels to ground.
The control unit program algorithm works on the principle of reading 58 teeth passing by the magnetic core of the DPKV, skipping two. The skipping of two teeth is a reference mark for determining the piston of the first (fourth) cylinder in the top dead center position, from which the unit analyzes and distributes the switching signals that control the opening of the injectors and the spark on the spark plugs over the engine operating strokes.
The control unit detects a short-term failure in the synchronization system and tries to resynchronize the control process. If it is impossible to restore the synchronization mode (lack of contact on the DPKV connector, cable break, mechanical damage or broken master disk), the system issues an error signal to the instrument panel, lighting the Check Engine warning lamp. The engine will stall and it will be impossible to start it.
The crankshaft position sensor is a reliable device and rarely fails, but sometimes malfunctions occur due to the inattentive or negligent attitude of specialists servicing the engine.
For example, a VAZ-2112 has a 21124 engine (16 valves where the DPKV cable is located very close to the exhaust manifold) and the problem usually arises after a repair, when the chip on the cable is not secured to the bracket. When the cable comes into contact with a hot pipe, it melts, destroying the connection circuit and the car stalls.
Another example would be a poorly manufactured drive disc, the rubber coupling of which may rotate along the internal connection.
The electronic control unit, receiving a single signal from the DPKV, determines the position relative to the crankshaft at each moment of time, calculating its rotation frequency and angular velocity.
Based on sinusoidal signals issued by the crankshaft position sensor, a wide range of problems are solved:
- Determination at a given time of the position of the piston of the first (or fourth) cylinder.
- Control of fuel injection timing and injector open duration.
- Ignition system control.
- Control of variable valve timing system;
- Control of the fuel vapor absorption system;
- Ensuring the operation of other additional systems related to engine speed (for example, electric power steering).
Thus, the DPKV ensures the functioning of the power unit, determining with high accuracy the operation of its two main systems - ignition and fuel injection.
Before purchasing a DPKV to replace it, you need to clarify the type of device installed on the engine.
This component is located in a bracket, which is installed in the central area of the pulley on the generator drive. As a rule, on most modern cars it is not installed end-to-end, but with a gap of 1-1.5 mm near the structure of the toothed pulley itself.
For ease of disconnecting and adjusting the DPKV, a 50-70 cm wire is connected to it, which has the necessary connectors for keys. To align and adjust the position, you only need to adjust the washer secured above the seat of the element itself. Adjusting the washer can be done either by you yourself or by specialists at a car service center - in any case, it will allow you to avoid early breakdown of the engine cylinders and significantly reduce fuel consumption.
Crankshaft position sensor
Crankshaft position sensor location
If a malfunction occurs in the crankshaft sensor, the vehicle’s on-board computer is unable to set a number of characteristics necessary for the operation of the ignition system:
- Calculate the amount of fuel required for injection;
- Determine the right moment for injection;
- Change the angle of rotation of the camshaft;
- Determine whether ignition has occurred or not (relevant for gasoline engines).
Also interesting: Niva Chevrolet knock sensor - Auto magazine MyDucato
Examination
Checking the sensor is carried out in two stages: visual inspection and testing using a device. The check must begin with a visual inspection of the sensor and its power circuit.
Visual inspection
The sensor may stop transmitting readings due to contamination or an open circuit. Therefore, it is necessary to inspect the sensor for contamination and the power circuit for open circuits. The power circuit is also made of a special shielded wire, which helps protect signals from interference or current leakage. The slightest damage to the insulation can lead to unstable operation of the sensor.
The sensor also has a magnetic part, on which metal shavings often stick, which contributes to poor reading by the sensor.
Testing with the device
Checking the DPKV can be carried out using a special diagnostic tool or a Chinese ELM327 scanner, via ADC channels. These devices can also replace a regular household multimeter. Let's consider checking the sensor using a multimeter.
Although this test does not give a 100% result, it still makes sense to carry it out.
- We switch the multimeter switch to the resistance measurement parameter.
- We connect the probes of the device to the sensor and look at the readings
- The device should show a value from 500 to 700 Ohms
Such parameters are characteristic of a good, serviceable DPKV.
Step-by-step instructions for self-diagnosis
To check the condition of the DPKV we need a multimeter. The measuring device is available to many car enthusiasts. If you don't have it, you can purchase it at any auto store. The price is affordable.
- From under the bottom of the car, disconnect the terminals from the sensor.
- We bring the limit switches to the contacts;
- Turn on the multimeter, set the position of the regulator to “resistance”;
- We carry out actual measurements;
- We compare the obtained data with standards. If the arrow tends to infinity, the controller is working. If it goes to “zero”, it’s a breakdown. Normally, readings should be 550-750 Ohms.
Depending on the diagnostic results, the technician makes a decision on the advisability of further operation of the equipment.
Replacement
Replacement is quite simple and does not require any car repair skills.
- To replace it, you just need to remove the negative terminal from the battery;
- Remove the connector from the DPKV;
- Unscrew the sensor from the bracket;
- Pull out the sensor, install a new sensor in its place and reassemble in the reverse order.
Symptoms of DPKV malfunction
- Difficulty starting the engine “hot” or “cold”;
- When moving downhill, detonation occurs;
- Idle speed is unstable;
- Motor power decreases periodically;
- Acceleration dynamics are passive;
- Sudden engine stop.
However, these symptoms are signs of a number of other breakdowns. It is extremely important to conduct comprehensive diagnostics using digital equipment.
| Name / catalog item | Price in rubles |
| VAZ 21214-2123 OMEGA 173882 | From 350 |
| 2112-3847010 | From 350 |
| 21120-384701004 | From 350 |
| 21120-384701036 | From 350 |
Speed sensor – DS.
The brain uses the signal from the speed sensor to control the engine's idle speed. And support for “pickup” speed while the car is coasting. The actuator of this circuit is the idle air regulator, which controls the air supply bypassing the throttle valve. Enough theory, let's get closer to the people. In fakes based on this sensor, ahead of the original by an order of magnitude - the Chinese brothers. 8 out of 10 sensors that I held in my hands in stores and on the market were made in China. They work for three months, after which they announce their retirement as a “check engine.” What is the difference between the original and the pale one? In the photo, I indicated with arrows where the wires entering the connector are filled with varnish. The seam of the body, which consists of two parts, is also filled with varnish. Mao's heirs consider this unnecessary, and that is why the sensor dies after the onset of the first St. Petersburg slush.
Crankshaft sensor functions
As already mentioned, one of the obvious signs of DPKV problems is a complete engine stop. This happens as a result of the fact that malfunctions in its operation do not allow the power system to supply fuel in a timely manner, and the ignition system is not capable of igniting the fuel-air mixture at a given moment. Now let's look at why this happens.
The crankshaft sensor sends signals to the ECU indicating the position of the crankshaft at a certain moment, and also reports the direction of rotation of the shaft and indicates the rotation speed. Please note that on different cars, both the device itself and some functions of the DPKV may differ. This depends on the type of element installed. Devices can be:
- magnetic inductive type;
- Hall effect sensors;
- optical sensors;
The electronic control unit receives signals from the specified device, thanks to which the controller “knows” the position of the crankshaft in relation to TDC in the first and fourth cylinders, and also records the frequency and direction of rotation of the shaft. Based on this data, the unit generates signals to control the ignition timing, creates control pulses for injection nozzles, controls the operation of the fuel pump, etc.
How does he work
In order for the ignition timing to work synchronously with the movement of the pistons in the cylinders, information about the position of the crankshaft at each moment of time is necessary. There is a rigid mechanical connection between the connecting rods and the crankshaft: to track them, it is enough to read the angle of deviation of the crankshaft axis from the zero point.
For this purpose, a gear (58 teeth) is placed on the timing belt drive pulley. They do not participate in the operation of the timing pulley and are intended only for the crankshaft position sensor (CPS).
The position of these teeth is strictly calibrated relative to the entire timing system and piston connecting rods. The device itself is a Hall sensor with a permanent magnet that responds to the passage of a metal object in close proximity. That is, the rotation of the crankshaft with a gear generates a series of pulses on the sensor. As a result, the ECU receives data on the position of the pistons in real time.
Video on the topic
Good publicity
After the publication of my article on the topic of oil seals for the Niva, requests began pouring in to write the same regarding bearings and sensors for the 21214 engine, which is installed on Nivas, Niva-Ms, crocodiles and Shnivas. I’ll begin to slowly talk about “trouble-free” sensors, that is, those that you install and forget about for a very long time.
A few general words. Why did this question even arise? Let me give you an example: such garbage as a throttle position sensor (TPS). Since the electronics of our injector are taken entirely from their front-wheel drive counterparts, and their number is very large, a very large number of companies make spare parts for them, and there is no need to talk about the Chinese brothers at all. For some time I even saved up faulty TPS from different manufacturers in a box, after 7 I got lost and threw everything away)) While the factory supplies only two manufacturers.
Another example is the speed sensor. When it’s burned out, it happens that when driving through a puddle, the “check engine” lights up, or the engine simply starts to stall when coasting and nothing lights up. And when you reach the service level, like a wartime exterminator, suddenly the defect disappears. This means that water got inside the case and then also leaked out. So all is well......until the next puddle. One of the most basic sensors is the mass air flow sensor (MAF) , so a separate detailed article is devoted to it.
Causes of premature wear of the DPKV
- long-term operation without intermediate prevention;
- manufacturing defects;
- third-party mechanical damage;
- ingress of sand, dirt, metal shavings;
- sensor breakage due to crankshaft teeth;
- damage to the DPKV during repair work;
- short circuit in the on-board circuit.
Recommendations for care and maintenance of the controller
- strictly comply with the car manufacturer's regulations;
- do not violate the terms of technical inspection, even when the factory warranty has expired;
- buy and install mainly original parts, the catalog numbers of which correspond to the factory markings;
- Carry out the installation work yourself if you have sufficient experience, otherwise use the services of professional workshops;
- Do not install parts or accessories from other technical equipment, even if they are similar in appearance. Full functionality is not always guaranteed.
The average service life of the DPKV is 80,000 km or more.
Methods of checking in garage conditions
When your car's engine suddenly "dies", you need to remove the sensor and perform the diagnostics described below. If the motor continues to operate with signs of instability, perform the following manipulations:
- Thoroughly clean the device body with a rag moistened with an organic solvent - white spirit, turpentine or other degreaser. Pay special attention to the end facing the toothed pulley.
- Make sure the fastening is secure. Due to a loose screw, the sensor may move away from the metal teeth, as a result, the gap will increase and the generated pulse will weaken.
- Clean the connector contacts from oxidation.
- Inspect the wiring for melting or breakage.
If the above actions do not produce results, the crankshaft sensor is dismantled and checked with a multimeter in 2 stages. At the first, the resistance between the terminals of the device is measured, which makes it possible to verify the integrity of the induction winding. Clean the contacts, turn on the ohmmeter and check the resistance between them. Normal readings are in the range of 500–700 Ohms; if the turns are shorted, you will get a zero or reduced value; if there is a break, you will get infinity.
At the second stage, the performance of the element is tested according to step-by-step instructions:
- Switch the multimeter to voltage measurement mode, the maximum threshold is 200 millivolts.
- Securely attach the wires to the contacts of the sensor block (for example, with alligator clips).
- Take any metal tool - a wrench, a large screwdriver or something similar. Apply and tear it sharply from the magnetic core of the element, holding the body with your hand. The voltmeter should show voltage surges.
Advice. If the crankshaft sensor is OK, check the wiring with an ohmmeter. Perhaps the reason lies there.
Further actions are as follows: the broken crankshaft speed meter is replaced with a new one; the part cannot be repaired. The working sensor is installed back, maintaining the gap, and the troubleshooting continues in another place.
A few words about how to check the crankshaft sensor on the road when you don’t have a multimeter or other diagnostic tools. You will need 2 wires and an LED light bulb from any car lamp (for example, an interior lamp). For convenience, unscrew the element and connect the lamp to the connector, then apply a wrench to the magnet, as described above. A working sensor will cause the LED to flash.
