Car Diagnostic Equipment
This is a device designed to diagnose the electronic “filling” of the machine. It does not have its own sensors, but connects to the computer and reads information from the system. Since modern cars are “stuffed” with an ECU, it is sometimes impossible to find and eliminate some types of malfunctions without a scanner. Using the autoscanner, you can get ECU passport data, delete errors, activate equipment, reprogram the unit, change mileage and many other functions.
Car scanner design
Motor testers and oscilloscopes
Oscilloscope – a device that allows you to graphically or numerically obtain information about the operation of a particular system and draw conclusions about its health by comparing the data with standard ones. Modern oscilloscopes are equipped with a number of additional sensors, allowing the device to partially perform the functions of a motor tester.
Motor tester – combines the functions of an automobile oscilloscope and a device testing the operation of electrical equipment of an engine. Unlike the scanner, the motor tester receives information from its sensors, and not from the computer.
In the oscilloscope mode, the motor tester provides information on the adequate operation of the ECU sensors, the parameters of the control signals from the ECU to the actuators of the systems. Checks the parameters of the ignition system circuits, etc. In tester mode, it diagnoses the correct operation of various components of the engine systems. For example, a change in pressure in the engine cylinder, a drop in speed when the cylinder is turned off, a vacuum in the intake manifold, inrush current testing, etc..
Testing individual systems
Odometer Corrector. The main function of the device is to change the speedometer readings. In addition to changing the available data, the device can be used as a programmer. For example, when changing tires of a smaller size to a larger one, to correct the error of the speedometer, you need to make changes to the computer.
Many correctors are equipped with a set of additional functions and can be used as testers and programmers of other car systems. For example, testing airbags, determining the access code of anti-theft systems and others.
Diagnostic equipment features
1. Obtaining information about the system, engine and car (passport data): vehicle identification number (VIN), controller software version and number (software), software preparation date, engine and control system type, spare parts order number.
2. Obtaining information about the values of the main parameters of the system.
The controller transmits a table of values of the current system operation parameters, and the tester displays them on the display. Values are displayed in physical quantities or as graphs of changes over time. A typical set of parameters is as follows: coolant temperature, on-board voltage, crankshaft rotation speed, throttle position, engine air mass, ignition timing, air-fuel composition control parameters, idle control parameters.
In addition to the parameter values, the tester can receive signal voltage from the system sensors from the controller.
By analyzing the values of the current parameters, it is possible to identify malfunctions in the system that are not determined by the self-diagnosis functions. For example, the throttle position is 5%, and the accelerator pedal is completely released – in this case, the throttle position sensor is faulty, or the problem is in the mechanical part.
3. Obtaining information from the controller memory about malfunctions in the system .
Error code. Each system fault is coded according to the international standard with a five character code. For example, P0122. The first letter “P” indicates that the error refers to the engine management system. The following “0” symbol indicates that this error is defined by the standard (maybe “2”). For errors not included in the standard, but determined by the manufacturer, this symbol will be “1” or “3”. The following combination of characters “12” indicates a throttle position sensor. The last character indicates the type of error, in our case “2” is the low signal level from the sensor.
Status Flags. This is additional error information. They show how things are going with this malfunction at the moment: active or not, random or constant, leads to the ignition of the diagnostic lamp or not, affects the increase in toxicity or not. For different controllers, there is a different set of status flags. Some controllers can also inform the tester additionally how many times a malfunction occurred, the time after the controller was reset, and up to three values of the system operation parameters at the time of fixing the error.
Freeze frame. This is a fixed (frozen) list of system parameter values at the time of the malfunction. By examining these values, you can determine when (at what temperature, crankshaft speed, load, vehicle speed) a malfunction occurred. This will help determine the cause of the error. Freeze Frame – a standard list of parameters whose values should be fixed, but manufacturers of control systems or cars have the right to choose their own set from this list.
On command from the diagnostic tester, you can clear the controller error memory.
4. Launching tests of checking executive devices of the system .
When conducting diagnostic work, there is a need to check the operability of the actuators of the system. In this case, the tester gives a command to turn the device on or off. For example, when measuring the balance of nozzles, before each measurement, it is necessary to have a working pressure in the fuel system (you need to turn on the electric gas pump periodically). Turning on the fuel pump relay can be done using the tester.
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