JPH0776732B2 - Vehicle diagnostic system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle diagnostic system for diagnosing a failure of a plurality of electronic control units mounted on a vehicle.

[Prior Art] In recent years, an engine mounted on a vehicle has been designed to electronically control the air-fuel ratio, etc. to realize comfortable drivability, purify exhaust gas, save fuel, and improve engine output. Has been.

When this electronic control system fails, it becomes difficult to control the engine accurately, which leads to deterioration of drivability, exhaust emission, fuel consumption, and engine output reduction.

For this reason, a connector is provided between the sensors and the control circuit, or between the actuators and the control circuit, as disclosed in Japanese Utility Model Laid-Open No. 60-25974 and connected to this connector. Although there is a configuration in which a plurality of determination circuits, holding means, and display means are provided to detect an abnormality, a plurality of connectors, determination circuits, holding means, and display means are required, which complicates the configuration.

In order to deal with this, recently, an external device such as a vehicle diagnostic device is connected to an electronic control device mounted on a vehicle to enable bidirectional communication between the electronic control device and the vehicle diagnostic device. The electronic control unit internal data for each actuator and the electronic control unit internal data for each actuator are read based on the output signal of each sensor in the electronic control unit, and a failure diagnosis of the electronic control unit is performed.

However, a vehicle is equipped with an electronic control unit that performs engine control, transmission control, brake control, cruise control, etc. as a plurality of control units, and when diagnosing a failure of these control units, the connector of each control unit is used. Must be connected to the connector of the vehicle diagnostic device, which not only causes an increase in the number of connectors but also a cost increase, but also makes the diagnostic work complicated, and in the case of a failure related to a plurality of electronic control devices, There is a problem that diagnosis work is not easy and it takes time to find a failure.

In addition, in Japanese Patent Laid-Open No. 62-150135 (first prior art example),
A plurality of electronic control devices mounted on the vehicle are connected via a network by a data bus, an input and a display device are connected to the data bus, and at least one of the plurality of electronic control devices is connected from the input and display device. To output a control command signal for controlling the operation of the selected electronic control device, control the operation of the selected electronic control device, and input an operation state detection signal in the electronic control device to the input and display device. There is disclosed a technique that makes it possible to easily inspect the operating states of the sensors and actuators set in each control system by displaying the above.

In addition, Japanese Patent Laid-Open No. 62-161038 (second prior example) discloses that
By connecting a plurality of electronic control units mounted on the vehicle via a network with a data bus, enabling the shipping inspection monitor device to be attached to and detached from this data bus, and issuing an inspection command from the shipping inspection monitor device, There is disclosed a technique of using at least one of the electronic control devices for diagnosis for checking whether or not each electronic control device is normally connected to the data bus.

[Problems to be Solved by the Invention] However, in the first prior art example, how to select a corresponding electronic control device from a plurality of electronic control devices by input and display devices and how to select corresponding data Since there is no specific disclosure, the technique disclosed in the first prior art example cannot be applied to the vehicle diagnosis system of the present invention as it is. Further, when the data request signal is output from the vehicle diagnostic device to the network, the data request signal is input to all of the plurality of electronic control devices, and it is necessary for each electronic control device mounted on the vehicle to cope with this. That is,
When a data request signal is input to each of the plurality of electronic control devices from the vehicle diagnosis device, unless each electronic control device performs appropriate processing, unnecessary calculation load is applied to the electronic control device not specified by the vehicle diagnosis device. May increase and affect normal control processing in the electronic control unit.

Further, in the second prior art example, it is only possible to diagnose whether or not each electronic control device is normally connected to the data bus, and it is not possible to diagnose input / output data in each electronic control device. Further, since one of the plurality of electronic control devices is used for diagnosis, in the electronic control device for this diagnosis,
There is also an inconvenience that a normal control process is hindered by a calculation load for diagnosis.

In view of the above circumstances, the present invention reliably specifies an electronic control device according to an operation input from an operation input means of a vehicle diagnosis device, and surely obtains necessary data from the specified electronic control device in the vehicle diagnosis device. A vehicle diagnosis system that can be transmitted to perform an accurate failure diagnosis and can prevent the electronic control device from affecting the normal control processing without unnecessarily increasing the calculation load in each electronic control device. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of electronic control devices mounted on a vehicle and connected via a network, and each electronic device connected to the network by bidirectional communication. In a vehicle diagnostic system including a vehicle diagnostic device for diagnosing input / output data of a control device, an external connection port for detachably attaching the vehicle diagnostic device to the network is provided, and the vehicle diagnostic device is provided with an operation input unit. A request signal consisting of designation information and a data request command for designating one of the electronic control units according to an operation input is output to each electronic control unit via the network, and data from each electronic control unit is received. Further, the electronic control unit receives the request signal and the picked-up data To the vehicle diagnostic device, and when the designation information in the request signal designates another electronic control unit, the processing currently being executed is continued and the own electronic control unit is designated. In some cases, the present invention is characterized by further comprising a selection means for interrupting the processing currently being executed and picking up data corresponding to the data request command.

[Operation] With the above configuration, when the vehicle diagnostic device is connected to the external connection port of the network connecting the plurality of electronic control devices mounted on the vehicle, the operation from the operation input means is performed when diagnosing the input / output data in the electronic control device. A request signal consisting of designation information and a data request command for designating one of a plurality of electronic control units according to an input is transmitted from the vehicle diagnostic device to each electronic control unit via the network and received by each electronic control unit. To be done. Then, in each electronic control device, when the designation information in the received request signal designates another electronic control device, the process currently being executed is continued,
When the self is designated, the processing currently being executed is interrupted, data corresponding to the data request command of the request signal is picked up, and transmitted to the vehicle diagnostic device via the network.

Embodiments of the Invention Embodiments of the present invention will be described below with reference to the drawings.

1 shows a schematic side view of a vehicle, FIG. 1 (b) is a front view of a vehicle diagnostic device, and FIG.
FIG. 3 is a circuit configuration diagram of each electronic control device and vehicle diagnostic device. FIG. 3 is a functional block diagram of each electronic control device and vehicle diagnostic device. FIG. 4 (a) is a flowchart showing an operation procedure of the vehicle diagnostic device. FIG. 6B is a flowchart showing the operation procedure of the electronic control unit.

In FIG. 1, reference numeral 500 is a vehicle such as an automobile, 501 is an electronic control unit (E) mounted on the vehicle 500 for performing air-fuel ratio control, etc.
CU is an engine control unit, 502 is a transmission control unit that is an ECU, 503 is a brake control unit that is an ECU that performs anti-lock brake control, and 504 is a calculation process that obtains various information necessary for running the vehicle. , A cruise control unit consisting of an ECU for controlling constant speed running.

As shown in FIG. 2, the ECUs 501 to 504 are connected to a power source BV via a relay RY1 which is opened and closed by a key switch SW10, central processing units (CPU) 501a to 504a, and RAM 501b to
504b, ROM 501c to 504c, non-volatile RAM (backup
RAM) 501d to 504d and input interface 501g to 504g
And output interfaces 501e to 504e respectively, and the RAMs 501b to 504b store temporary parameters that have been subjected to various kinds of arithmetic processing or control maps and the like.
Programs and fixed data are stored in the ROMs 501c to 504c.

Then, the ECU 501 receives the cooling water temperature sensor 9, the O2 sensor 10, the suction pipe negative pressure sensor via the input interface 501g.
11, air conditioner switch SW1, vehicle speed sensor 13, accelerator switch SW5, throttle opening sensor 15, neutral switch SW3, taking in each signal from the engine speed sensor 17, according to the program stored in the ROM501c, data processing, Once stored in the RAM 501b, the CPU 501a performs various arithmetic processing based on the stored data, and based on the arithmetically processed data, the canister purge via the output interface 501e and the drive circuit 501h. A control signal is output to the solenoid 19, the EGR actuator 20, the idle control actuator 21, the ignition coil 22, the injector 23 and the like to perform necessary engine control.

Further, the ECU 502 takes in each signal of the engine speed sensor 17, the vehicle speed sensor 13, the accelerator switch SW5, the throttle opening sensor 15, and the neutral switch SW3 via the input interface 502g, and outputs a shift command to the interface 502e, which is driven. A / T actuator 5 via circuit 502h
25, and shift control of an automatic transmission (not shown) is performed according to the operating state.

Further, the ECU 503 takes in each signal of the brake switch SW6 and the wheel speed sensor 527 via the input interface 503g, performs control calculation for antilock according to the control program of the ROM 503c, and outputs the control signal to the output interface 503e. , To the ABS brake actuator 528 via the drive circuit 503h to perform anti-lock (anti-skid) brake control.

Further, the ECU 504 takes in signals from the constant speed traveling setting switch SW7 and the vehicle speed sensor 13 via the input interface 504g, and controls the throttle actuator 530 via the output interface 504e and the drive circuit 504h to control the constant speed traveling. Brake switch SW6, accelerator switch SW5, neutral switch SW3, deceleration switch SW8,
When a signal from each switch of the resume switch SW9 is input through the input interface 504g, the constant speed traveling is canceled or the constant speed traveling accompanied by acceleration / deceleration is reset.

Further, the ECUs 501 to 504 are connected to the respective input interfaces 501g to 504g and the output interfaces 501e to 504e to the bus line 500a forming a communication line for transmission and reception, and to the external connection connector 24 forming an external connection port. The input / output connector 26 of the vehicle diagnostic device 25 is connected to the external connector 24 via the adapter harness 27.

This vehicle diagnostic device 25 is provided in a dealer service station or the like, and a control unit 28, a power supply circuit 29, etc. are provided inside the vehicle diagnostic device main body 25a, and a plurality of light emitting diodes (LED) D1 are provided outside. An indicator unit 30 having D10, a display 31, a keyboard 32, and the like are provided. Further, a memory cartridge 34, which can be connected from the outside, is connected to the control unit 28 via the connector 33 with respect to the vehicle diagnostic device body 25a.

The control unit 28 includes a timer 3 including a CPU 36, a RAM 37, a frequency counter, etc., which are connected to each other via a bus line 35.
8 and an I / O interface 40 are provided.

Output signals of the various switches are input to the input side of the I / O interface 40 via the output interfaces 501e to 504e of the ECUs 501 to 504. Further, the indicator unit 30 is connected to the output side of the I / O interface 40, and by turning on and off the above switches, the LED of the indicator unit 30 corresponding to the switch lights up (or blinks) and goes out. However, the operation of each switch can be confirmed.

Further, on the input side of the I / O interface 40, the mode selection signal of the keyboard 32, the output interfaces 501e to 504e of the ECUs 501 to 504 to the drive circuits 501h to 504h.
Various control signals that are output to, and output signals of the various sensors described above are input. Further, the output side of the I / O interface 40 is the input interface 5 of the ECU 501 to 504.
01g to 504g and the display 31 are connected.

Further, the memory cartridge 34 can be selectively connected to the programs of the ECUs 501 to 504, which are different for each vehicle type, through the connection connector 33 so that the vehicle diagnostic device body 25a itself has compatibility. In addition, the ROM 41 that stores a diagnostic program, fixed data, and the like according to the vehicle type program is stored inside.

Further, the timer 38 is provided with a clock pulse oscillating element 42 which outputs a synchronizing signal.

Further, a power supply circuit 29 connected to the control unit 28 is connected to the power supply BV of the vehicle 500 via an ON / OFF operation switch SW4.

Next, each electronic control unit (ECU) 501 to 504 and vehicle diagnosis 2
The function of 5 will be described with reference to FIG.

The functions of the respective ECUs 501 to 504 are calculation means 551a to 551d for calculating signals from respective sensors and switches,
Driving means (driving circuit) 501h to 504h for outputting a driving signal to each actuator, data pickup means 552a to 552
d, decryption means 553a-553d, and communication means 554a-554d. The communication means 554a to 554d are connected to the bus line 500a, and each of the above-mentioned bus lines 500a connects the above-mentioned bus lines 500a.
A network in which the ECUs 501 to 504 can communicate with each other, that is, a vehicle-mounted local area network (LAN) is formed. Further, the external connection connector 24 is connected to the bus line 500a.

Here, the vehicle diagnostic device is connected to the external connector 24.
When 25 is connected, a LAN consisting of the ECU 501 to 504 and the vehicle diagnostic device 25 is configured, and bidirectional or one-way communication is possible between any of the ECU 501 to 504 and the vehicle diagnostic device 25. In addition, bidirectional communication between arbitrary devices becomes possible.

Therefore, when performing a failure diagnosis of the ECU501 ~ 504, when various request signals are transmitted from the vehicle diagnostic device 25, the request signal is received by the communication means 554a ~ 554d of the ECU501 ~ 504, the decoding means 553a ~ The content is interpreted at 553d. The decoding means 553a to 553d instruct the data pickup means 552a to 552d to pick up predetermined data according to the contents of the decoding, and the data pickup means 55
2a to 552d pick up various data calculated by the calculation means 551a to 551d or fixed data stored in the ROMs 501c to 504c, and the above communication means 554a to 554d.
Outputs the above data to the bus line 500a.

That is, in the present embodiment, the data pickup means
552a ~ 552d and the decoding means 553a ~ 553d constitutes a selection means, a plurality of vehicle diagnostic device 25 transmitted from the
A request signal including designation information and a data request command that designates any of the ECUs 501 to 504 is transmitted to each of the ECUs 501 to 504.
When received via the communication means 554a to 554d, each ECU 501
When the designation information in the request signal is determined by the selection means in ˜504 and the designation information designates another electronic control unit, the processing currently being executed in the ECU is continued and the own ECU is designated. When the E
The processing currently being executed in the CU is interrupted, the data corresponding to the data request command is picked up, and transmitted to the vehicle diagnostic device 25 via the communication means.

In addition, the vehicle diagnostic device 25 includes a communication unit 56 and a data calculation unit.
57, a keyboard interpretation means 58, a display drive means 59, a keyboard 32 as an operation input means, and a display 31.

The diagnostic mode input from the keyboard 32 by the diagnostic operator's keyboard operation is interpreted by the keyboard interpreting means 58, and the EC is transferred from the communicating means 56 to the bus line 500a.
A request signal including specification information for specifying U and a data request command is output. The request signal output to the bus line 500a is received by the ECU 501 to 504, and as a result, the ECU 501 to 504 is picked up corresponding to the data request command from the ECU designated by the designation information in the request signal. The data transmitted is received by the communication means 56 and calculated by the data calculation means 57,
It is displayed on the display 31 via the display driving means 59.

Next, the vehicle diagnostic device 25 and each electronic control unit (ECU) 501-
The operation procedure in 504 will be described based on the flowcharts of FIGS. 4 (a) and 4 (b).

(Vehicle Diagnostic Device) First, the input / output connector 26 of the vehicle diagnostic device 25 is connected to the external connection connector 24 of the vehicle 500 directly or via the adapter harness 27, and then the power source of the vehicle diagnostic device 25 is turned on by the operation switch SW4. Turn on.

Then, in step 102, the vehicle diagnostic device 25 is initialized, and then in step 103, the vehicle diagnostic device 25 is initialized.
Outputs a model code request signal to ECU 501.
The model code is stored in advance in the ROM 501c of the ECU 501.

Here, the request signal output from the vehicle diagnostic device 25 includes, for example, address information as an example of designation information of the vehicle diagnostic device 25 and the control unit, a data request command, and the like, and the model code request signal is the vehicle diagnostic device. 25 and engine control unit (ECU501) address information, and
The model code request signal is transmitted to each of the ECUs 501 to 504 in this order.

(Electronic control device) When a request signal is transmitted from the vehicle diagnostic device 25 to each ECU 501 to 504, each ECU 501 to 504 is interrupted and each ECU is
The currently running task is interrupted at 501 to 504, and step 201
Then, the request signal from the vehicle diagnostic device 25 is received.

Next, proceeding to step 202, each of the ECUs 501 to 504 identifies its own address from the received request signal, and if it is its own address, proceeds to step 203. In this case, since the address of the engine control unit (ECU501) has been transmitted, only the ECU501 proceeds from step 202 to step 203, and the ECU502
~ 504 exits the routine from step 202 and ends the interrupt.

In step 203, the command transmitted from the vehicle diagnostic device 25 is interpreted, in step 204, the corresponding data is picked up, and the process proceeds to step 205 to transmit the data. In this case, since the data request command from the vehicle diagnostic device 25 is the model code request, the ECU 501 reads the model code data stored in advance in the ROM 501c and outputs the model code data to the bus line 500a. The model code data includes the address information of the vehicle diagnostic device 25.

(Vehicle Diagnostic Device) Explaining again the vehicle diagnostic device 25 side, in the vehicle diagnostic device 25, in step 104, the address for itself is identified from the model code data output to the bus line 500a in response to the ECU 501, and the vehicle diagnostic device 25 is identified. Data for device 25,
That is, it is determined whether the model code data has been received.
If it can be received, the process proceeds to step 105, and if it cannot be received, the process returns to step 104 to repeat the determination.

In step 105, the CPU 36 identifies the model and stores the received model code in a specific address of the RAM 37.
Next, the procedure proceeds to step 106, where the ROM of the memory cartridge 34
From the multiple tables stored in 41, select the table corresponding to the model code above. As a result, the table corresponding to the control unit of the vehicle is specified, and thereafter,
Diagnosis is executed according to the program stored in this table.

After that, when the diagnostic operator operates the keyboard, in step 107, the diagnostic mode input from the keyboard 32 is read. For example, when diagnosing the cooling water temperature data in the ECU 501 based on the output signal of the cooling water temperature sensor 9, the mode is input by the key operation of the keyboard 32 by the diagnostic operator (for example, F → 0 → 7 → ENT is input). Then, the CPU 36 of the vehicle diagnostic device 25 reads this mode and temporarily stores it in a predetermined address of the RAM 37.
The mode contents are interpreted and a program corresponding to the diagnostic mode is selected, and at the same time, fixed data such as an abbreviation and unit corresponding to the diagnostic mode is read from the ROM 41 and R
It is stored in the predetermined address of AM37.

After that, in step 108, together with the address information of the ECU 501, a transmission request signal of data corresponding to this diagnostic mode (for example, cooling water temperature data in the ECU 501 described above) is output to the bus line 500a.

(Electronic control device) At this time, in each of the ECUs 501 to 504, the interrupt program starts in response to the data transmission request from the vehicle diagnostic device 25. However, as described above, since the address designation in the transmission request signal is the ECU 501, 504 exits the program from step 202 and ends the interrupt.

On the other hand, the ECU 501 proceeds from step 202 to step 203,
A data request command from the vehicle diagnostic device 25, that is,
Interpret the cooling water temperature data request, and pick up the cooling water temperature data instead of the model code data in step 204,
Proceed to step 205, and collect the cooling water temperature data from the above bus line 5
Output to 00a.

(Vehicle Diagnostic Device) On the other hand, the vehicle diagnostic device 25 determines in step 109 that the ECU 501
The data signal output from is received, and the process proceeds to step 110.

In step 110, the received data is calculated and converted into a physical quantity (binary number data is converted into decimal number to be converted into numerical value data) and stored as numerical value data in a predetermined address of the RAM 37. Then, in step 111, the numerical data and fixed data such as the abbreviation and unit stored in the RAM 37 in step 107 are read out and output from the I / O interface 40 to the display 31 as a display signal.

As a result, the display 31 of the vehicle diagnostic device 25 displays the numerical data, the abbreviation, the diagnostic mode number (function number input by key operation), the unit, and the like. In the case of the above-mentioned cooling water temperature sensor diagnostic mode, as shown in FIG. 1 (b), the cooling water temperature abbreviation TW, function number F07,
The numerical value +14 of the cooling water temperature data and the unit degC are displayed. Then, the process returns to step 107 to wait for the next key input.

Here, when executing a new diagnostic item, for example, as a control unit other than the engine control unit (ECU501) described above, the wheel speed data based on the output of the wheel speed sensor 527 in the brake control unit (ECU503) is requested. If you do
Similarly, by inputting the corresponding mode by key operation of the keyboard 32 (for example, key inputting F → B → 1 → ENT), the mode contents are interpreted in step 107 as described above, and in step 108. , The transmission request signal of the wheel speed data in the ECU 503 corresponding to the diagnostic mode is sent to each ECU 501.
Output to ~ 504.

(Electronic control device) At this time, the ECU 501 transmits the cooling water temperature data described above, but the ECU 501 does not specify the address of the ECU 501 because it is a wheel speed data request to another ECU (ECU 503). And the transmission of the cooling water temperature data from the ECU 501 to the vehicle diagnostic device 25 is terminated.

At the same time, the ECUs 502 to 504 are interrupted, and only the ECU 503 proceeds to step 203 by the brake control unit designation address in the transmission request signal.
504 exits the program from step 202 and ends the interrupt.

The ECU 503 interprets it as a wheel speed data request by command interpretation in step 203, picks up the wheel speed data in step 204, proceeds to step 205, and transmits the wheel speed data.

(Wheel Diagnostic Device) On the other hand, the wheel diagnostic device 25 receives the wheel speed data in step 109, calculates the received wheel speed data in step 110, and converts it into a physical quantity to obtain numerical data. And
In step 111, a display signal is output to the display 31 and the wheel speed data is displayed numerically on the display 31.

As described above, with respect to the plurality of electronic control devices mounted on the wheels, only by connecting the wheel diagnostic device 25 to one external connection connector 24, for example, the engine control unit (ECU5
01), transmission control unit (ECU502), cruise control unit (ECU504) input vehicle speed sensor
The vehicle speed data in each ECU of the output signal from 13 can be diagnosed for each ECU by inputting the corresponding diagnostic mode from the keyboard 32 by key operation.

As a result, if the vehicle speed data in all the ECUs is abnormal, it can be diagnosed as a failure of the vehicle speed sensor 13, and if only the vehicle speed data in one ECU is abnormal, the ECU and the vehicle speed sensor 13 are Poor contact, short circuit,
Alternatively, the disconnection of the wiring and the failure of the ECU can be understood, and the failure diagnosis can be performed by organically connecting the systems.

In the present embodiment, an example in which the present invention is applied to a bus type LAN has been described, but it goes without saying that the present invention can also be applied to other types of LAN such as ring type and star type. In various types of LANs, the external connection port may be provided not only on a communication line in the network but also on a controller or the like for controlling communication of the entire network. Furthermore, the access method and transmission method are not limited to those in this embodiment.

[Effects of the Invention] As described above, according to the present invention, a vehicle diagnostic device is connected to an external connection port of a network for connecting a plurality of electronic control devices mounted on a vehicle to diagnose input / output data in the electronic control device. In doing so, a request signal composed of designation information and a data request command for designating any one of the plurality of electronic control units according to the operation input from the operation input means is transmitted from the vehicle diagnostic device to each electronic control unit via the network. If the specified information in the received request signal specifies another electronic control unit, the electronic control unit continues the process currently being executed and specifies itself. If it is, the process currently being executed is interrupted, the data corresponding to the data request command of the request signal is picked up, and the vehicle is transferred via the network. Since the electronic control device is transmitted to the diagnostic device, the electronic control device according to the operation input from the operation input means of the vehicle diagnostic device among the plurality of electronic control devices is reliably designated, and the data required by the designated electronic control device is transmitted. The fault diagnosis can be reliably transmitted to the vehicle diagnostic device, and accurate fault diagnosis can be performed. Further, fault diagnosis in which each system is organically coupled can be performed by a simple operation.

Further, each electronic control unit mounted on the vehicle picks up the data corresponding to the data request command of the above request signal by interrupting the processing currently being executed only when the designation information in the received request signal designates itself. Then, if the specified information in the received request signal specifies another electronic control unit, the processing currently being executed is continued, and therefore the calculation is unnecessary in each electronic control unit. It is possible to prevent the normal control processing in the electronic control device from being affected without increasing the burden.

[Brief description of drawings]

1 shows a schematic side view of a vehicle, FIG. 1 (b) is a front view of a vehicle diagnostic device, and FIG.
FIG. 3 is a circuit configuration diagram of each electronic control device and vehicle diagnostic device. FIG. 3 is a functional block diagram of each electronic control device and vehicle diagnostic device. FIG. 4 (a) is a flowchart showing an operation procedure of the vehicle diagnostic device. FIG. 6B is a flowchart showing the operation procedure of each electronic control unit. 25 ... Vehicle diagnostic device, 32 ... Keyboard (operation input means), 500 ... Vehicle, 501, 502, 503, 504 ... Electronic control device, 56, 554a, 554b, 554c, 554d ... Communication means, 24 ... External connection connector ( External connection port), 552a, 552b, 552
c, 552d …… Data pickup means (selection means), 553
a, 553b, 553c, 553d …… Decoding means (selection means), 550a ……
Bus line.

Claims (1)

[Claims] 1. A plurality of electronic control devices mounted on a vehicle and connected via a network, and a vehicle diagnostic device for connecting to the network and diagnosing input / output data of each of the electronic control devices by bidirectional communication. In the vehicle diagnostic system, the network includes an external connection port that allows the vehicle diagnostic device to be detachably attached, and the vehicle diagnostic device includes any one of the electronic control devices according to an operation input from an operation input unit. While outputting the request signal consisting of the specified information to be specified and the data request command to each electronic control unit via the network,
Communication means for receiving data from each electronic control device, and each of the electronic control devices further includes communication means for receiving the request signal and transmitting picked-up data to the vehicle diagnostic device, When the designation information in the request signal designates another electronic control unit, the process currently being executed is continued, and when it designates its own electronic control unit, the process currently being executed is interrupted and the above data is suspended. A vehicle diagnostic system comprising: a selection unit that picks up data corresponding to a request command.