Broken camshaft position sensor Symptoms, repair costs
Is it possible to repair the camshaft position sensor of your car?
A broken camshaft sensor (e-CMP) – a rare but not exceptional. Technology is technology, and from time to time it can fail. How to recognize a defective sensor and what to do with him then? Let us look at a hypothetical situation.
In order to ensure optimum performance of the engine, the minimum possible fuel consumption under all conditions of operation, as well as emissions and acceptable power characteristics, the engine has to control a lot of different useful sensors, or as they are called, electronic sensors. But among them is one that is directly responsible for managing the valves is the camshaft sensor.
The function of the camshaft position sensor
Camshaft sensor belongs to the family of Hall sensors. It consists of a semiconductor, through which flows a small current and which is installed near metal sprockets (called the encoder disk), located directly on the camshaft. When the engine is running, the reluctor ring teeth move along the semiconductor by changing its magnetic field and hence the current. The change is registered.
Sine wave of electromotive force (EMF) (increase in the amplitude of the sine wave notes the compression stroke of the 1st cylinder)
However, by itself, it was the change of the magnetic field can not determine the position of the camshaft relative to the camshaft position sensor DPRV. The trick is to install the camshaft gear defines a label for the formation of step changes in the magnetic field generated by the sensor. There are several ways: the label may be, as the ledge – tooth denotes top dead centre (TDC) for the first cylinder, or Vice versa, the recess on the drive timing, the essence of the work remains the same.
How do you know that has stopped working camshaft sensor?
But what matters and what is most tangible and therefore, an important signs of problems with sensor DPRV (“CMP”, English style): a lit yellow indicator on the instrument panel, the well-known “Check engine”, engine failure from the start, the loss of thrust/power, the motor may begin to stall. This is just the most noticeable symptoms associated with the fact that one of the possible culprits of irregular engine performance of the car is the CMP sensor. Read more about the faults of the nuances of working DPRV read here: Symptoms of a camshaft sensor
As soon as you are faced with similar problems, the second thing you need to make sure that Shalit this sensor, because, again, the failure is quite rare, and its symptoms by itself says nothing, the reasons can be a dozen and they can be completely unrelated to the CMP sensor. For example, lost traction? It may have failed hydraulically controlled clutch, a so-called Phaser on the intake camshaft. The engine runs unevenly? It is quite possible the case in spark plugs. And so on.
The first thing you (or the service center employees) should take – consider the error code that is recorded in the onboard computer of the car. Major errors can be of 5 pieces, each numbered from P0340 P0344 CMP to CMP and under each number cause of failure in the normal operation of the sensor will have its own, usually associated with improper signal from DPRV.
If connected to diagnostic connector OBD 2, on the screen appeared one of the above mistakes – rest assured, there is a problem with this sensor. Congratulations, you’re in luck! As it is repaired?
The objectives of the camshaft position sensor
While in the past it was enough to start the spark only depends on the crankshaft position and simultaneously to inject fuel into the cylinders by means of injectors, this method has been deprecated with the introduction of the Euro 4 standard from January 1, 2005.
From the internal combustion engine working on four stroke principle have a problem: the duty cycle of intake, compression, stroke and release occurs for two revolutions of the crankshaft. But how to calculate the ECU (onboard computer) what position is each of the pistons in the cylinders? Camshaft can help. Because it makes only one turn for all four beats, in accordance with its rotation can be read from the corresponding position of the piston in the cylinder in a given unit of time, i.e. when it should be energized on the spark plug or when exactly to make the operation of the injectors.
If you want to delve into the theory, we strongly recommend you to watch this extremely informative video:
Video taken from YouTube channel GrunBaum
The definition of this provision as possible sensor camshaft (CMP device). In practice, and the camshaft, and his colleague, crankshaft sensor, reported top dead center (ot) of the first cylinder to the control unit. This must happen simultaneously, otherwise the drive shaft will be a problem.
If there is a discrepancy in the sensors, it is likely that, as in the case of sagging of the chain or that moved on a few teeth of the belt, a yellow warning light engine appears on the dashboard as an alert, including the management of the engine in emergency mode.
The same applies mutatis mutandis to the diesel engine, except that there’s no spark igniting the fuel mixture and it demands precision injection time is much higher than in a gasoline engine.
Repair and cost of the camshaft position sensor
In electropathy camshaft mounted elements of a Hall sensor, which is sealed in a small plastic box, the repair of which is not provided. Requires replacement. Prices for popular models start from 300 to 5 – 6 thousand roubles for one sensor. Dealers, as a rule, the parts can be more expensive twice. It is worth remembering that these sensors may be several, but at the same time, they just will not fail, therefore, replacement will only be one of them.
What else is important to know about the sensor replacement?
First, as a rule, the sensor can be easily changed within 20 minutes even if the inexperience of the employee. Standard CMP is on the top cylinder head (cylinder head) somewhere near the front part of it where the gears of the camshafts.
Second, note the third time – the defects of the sensor due to wear and tear are very rare, and maybe before you run to the store for a new one, you should consider the electric the periphery. Often the sensor just enough to clean dirt or oily residue, which isolate the magnetic field of Hall sensors. Or problem in the oxidation of the terminals or broken electrical wires, supplying power to the Hall sensor.
To determine what happened and know if the sensor you can use diagnostics on maintenance station in such a tool as the oscilloscope. In the garage using a voltmeter is also quite possible to know the type of fault DPRV, but this is of course somewhat more complicated, because you need to have some knowledge on electrical engineering.
For example, it is possible to determine the presence of voltage in the wires leading to the sensor, for which a chip removing cables from the CMP sensor (after disconnecting the battery, throwing off the negative terminal) and the ignition on, check using a voltmeter the voltage (before turning on the ignition, the negative terminal of the battery back into place). If the device does not show anything – there is a break in the mains.
If the current is, but the symptoms of the malfunction will not be likely to blame himself DPRV. The Council experienced in the measurement of the following: removing the camshaft position sensor, throwing off previously with battery negative terminal. The tester is attached to the first and second chip (see video below) and any large metal objects check statement, issued by the device. The closer the metal object, the lower the voltage will be displayed on the screen of an electronic tester than on metal, the higher the voltage. If nothing changes, the problem is in the sensor and it needs to be replaced.
On approximate algorithm of actions the following short video which shows in more details how to make measurements:
Video taken from YouTube channel Cdelaysam
By the way, most sensors do not change because of their physical deterioration, and for quite another reason: the gasket between the sensor and the cylinder head, over time, hardens, starting to pass oil to the outside, contaminating the device.
In most cases this o-ring is part of the sensor, so you have to replace the whole device. Remove the o-ring of course, but the material needs to be matched replacement should be heat resistant, and the ring itself in exactly the same dimensions of model with rubber products.
How much is the replacement electronic devices DPRV?
Everything will depend on the model of your car and car service. In Moscow, price tags start from 1,000 and go up to 2,000 – 2,500 rubles, not counting the cost of the device. Therefore, if you are not confident in your forces, we advise you to call the service station. There are professionals fast prediagnostic and conduct the necessary repairs. Well, if you know a lot or do you have a friendly mechanic is ready to help you, go for it, save a thousand or two rubles.