GB2311638A

GB2311638A - Diagnostic apparatus for control system for automotive vehicle

Info

Publication number: GB2311638A
Application number: GB9706230A
Authority: GB
Inventors: Koji Uehara; Kunihiro Abe; Haruo Fujiki
Original assignee: Fuji Jukogyo KK; Fuji Heavy Industries Ltd
Current assignee: Subaru Corp
Priority date: 1996-03-27
Filing date: 1997-03-26
Publication date: 1997-10-01
Also published as: DE19712924A1; JPH09257660A; KR970066544A; GB9706230D0

Description

2311638 DIAGNOSTIC KPPARATUS FOR CONTROL SYSTEM FOR AUTOMOTIVE VEHICLE The

present inVention relates generally to a diagnosing apparatus for a control system for an automotive vehicle. More specifically, the invention relates to a diagnosing apparatus for reading data in an electronic controller mounted in an automotive vehicle to diagnose a fault in a control system including the electronic controller.

Recent control systems for automotive vehicles are complicated, so that it is required to provide a fault diagnosing apparatus which can simply read data from an electronic controller mounted on the vehicle.

As an example of a diagnosing apparatus of this type, Japanese Patent Publication No. 7-76737 filed by the applicant of the present application discloses a hand-held diagnosing apparatus which regards the general usability as important. This apparat us can read and display data in an electronic controller for an automotive vehicle by a simple key operation of a keyboard so that a mechanic can simply check a control system for the vehicle.

Such a hand-held diagnosing apparatus is designed to regard a man-machine interface, such as a keyboard and a display, as Important. In addition, as an example of technique relating to a back light for a display, Japanese Patent Laid-Open No. 1-237810 discloses that a back light of a display unit is turned of f when no key input is carried out for a predetermined period of time.

In the aforementioned hand-held diagnosing apparatus, the number of keys is restricted because of limitations of size of a keyboard. Therefore, when different functions are assigned to the same key and at selecting a key function for operation, it is difficult for an operator to recognize the current functional mode of the key by appearances.

2 In order to eliminate this problem, functional modes may be displayed on the screen. Alternatively, a lamp or the like may be provided on the body so that the lamp is turned on when the functional mode of the key is switched. However, In these cases, there are problems in that the scope for displaying data on the screen is decreased, the visual recognizability is lowered to cause operational error, and so forth.

it is therefore an object of the present invention to eliminate the aforementioned problems and to provide a diagnosing apparatus which can surely distinguish the current functional mode of a key, to which a plurality of functions are assigned, without decreasing the display area for a diagnostic information.

In order to accomplish the aforementioned and other objects, according to one aspect of the present invention, a diagnosing apparatus is connected to an electronic controller mounted on an automotive vehicle to read data out of the electronic controller by operating a key to diagnose a fault of a control system containing the electronic controller for the vehicle. The diagnosing apparatus comprises: key lighting means for lighting the key as a back light; key function switching means for switching a function of the key in response to a selected input, the key being previously set so as to have a plurality of functions, and key lighting control means for changing a lighting state of the corresponding key lighted by the key lighting means when the function of the keyis switched by the key function switching means.

The key lighting control means may change the lighting state of the corresponding key by a lighting color or brightness. 1 That is, in the aforementioned diagnosing apparatus, when a function of a key, which is previously set to have a plurality of functions, is switched in response to a selected input, the lighting state of the back light for the 3 corresponding key is changed so that it is possible to easily distinguish the change of the function of the key. In this case, the lighting state of the back light can be changed by the lighting color or brightness., With this construction, since the lighting state of the back light for the corresponding key changes when the function of the key, which is previously set to have a plurality of functions, is switched in response to the selected input, it is possible to surely distinguish the current functional mode to prevent misoperation. In addition, since it is not required to indicate the functional mode of the key on the display screen, the display area for diagnosis information is not decreased Some embodiments of the invention will now be described with reference to the following drawings:

FIG. 1 is a block diagram of the basic construction of a diagnosing apparatus according to the present invention; FIG. 2 is a f lowchart of the f ront part of a menu processing routine according to the present invention; FIG. 3 is a flowchart of the rear part of the menu processing routine according to the present invention; FIG. 4 is a schematic view of a menu screen of a select monitor according to the present invention; FIG. 5 is a schematic view of a menu screen for a fault diagnosis tor an automotive vehicle, according to the present Invention; FIG. 6 is a schematic view of a menu screen for data display and memory according to the present invention; FIGS. 7(a), 7(b) and 7(c) are schematic views of menu screens for graph-display setting according to the present invention; FIG. 8 is a schematic view of a screen for a graph of engine speed according to the present invention; FIG. 9 is a block diagram illustrating circuits for an on-vehicle electronic controller and a fault diagnosing apparatus according to the present invention; FIG. 10 is a circuit diagram of a key lighting 4 driving circuit according to the present invention; and FIG. 11 Is a schematic view of the exterior of a diagnosing apparatus connected to an on-vehicle electronic controller, according to the present invention.

Referring now to the accompanying drawings, the preferred embodiment of a diagnosing apparatus for an automotive vehicle, according to the present invention, will be described below.

In FIG. 11, A denotes a hand-held diagnosing apparatus which will be hereinafter referred to as a "select monitor". The select monitor A is connected to an electronic controller C mounted on a vehicle B, such as an automotive vehicle, to read various data containing input and output data for the electronic controller C using bilateral communication, to diagnose the fault of a control systern containing the electronic controller C for the vehicle B. The select monitor A has a general purpose interface capable of being connected to various on-vehicle electronic controllers, regardless. of the type of vehicle or as a vehicle manufacturer. In addition to a fault diagnosing as a base function, the select monitor A also has various expanded functions which contain: a measuring function for measuring voltage, resistance, pulse signal or the like; a communication function with a computer using a wire communication, a radio communication, an optical communication or the like; and a data memory extending function. Basically, the select monitor A is designed to select various processings on the basis of a menu facility of a hierarchical structure.

The select monitor A includes a display 30, such as a liquid crystal display with a back light, and an indicator part 31 comprIsing a plurality of light emitting diodes or the like, on the left side of a front face thereof. The select monitor A also includes a keyboard 32 serving as a keystroke section on the right side of the front face. Moreover, the left end portion of the select monitor A is designed to be connected to a memory cassette 60 which will be described later.

The keyboard 32 is capable of changing the function of.a key in accordance with the purpose. As shown in FIG. 4, the keyboard 32 includes direction keys 45, 46, 47 and 48 on the center thereof. On the tops of the direction keys 45, 46, 47 and 48, the signs " T ", " 1 ", D-.. and are expressed, respectively. The keyboard 32 also includes a shift key 49 having a character "S", a selection key 50 having a character "C", an YES key 51 having a character "Y" and a NO key having a character "N" at the corners thereof. Moreover, the keyboard 32 includes function keys 53, 54, 55 and 56 at the bottom portion thereof, the function keys 53, 54, 55 and 56 having characters "FI", I F2", "F3" and "FC, respectively. As described later, each of the keys has a light emitting element on the bottom thereof, so that the light from the light emitting element Is transmitted to serve as a back light.

In a case where the data in the electronic controller C mounted on the vehicle B are read to diagnose the f ault thereof, a diagconnector 33 provided on the select monitor A is connected to an external connector 2a of the electronic controller C via a diagcable 34 as shown in FIG. 11. Then, a power switch (not shown) provided on the side of the select monitor A Is turned on, and a desired item is selected by the keyboard 32 from a menu indicated on the display 30, so that It is possible to easily diagnose the fault of each part.

As the electronic controller C mounted on the vehicle B, there are various electronic controllers such as a controller for a power train control for an engine and an automatic transmission, a controller for a body control for an air conditioner, various information systems and so forth, and a controller for a vehicle control such as a suspension control and a cruise control. In this preferred embodiment, the present invention will be explained using as an example the diagnosis of an engine control unit (ECU) 2 for controlling an engine.

6 As shown in FIG. 9, the ECU 2 is formed as a microcomputer which generally comprises: a CPU 3 serving as a main processor; a ROM 4 in which f ixed data such as an engine control program and various maps are stored; a RAM 5 In which data after processing output signals of various sensors and switches and operated data are stored; an input interface 6 for inputting signals from the various sensors and switches; and an output interface 7 for outputting control signals to various actuators, wherein CPU 3, ROM 4, RAM, input interface 6 and output interface 7 are connected to each other via bus lines. The ECU 2 also includes peripheral circuits such as a constant -voltage supply circuit 8 for supplying constant voltages to the respective parts, and a drive circuit 9 for driving the actuators in response to the signals from the output interfaces 7.

The data inputted via the input interface 6 include a coolant temperature indicative signal outputted from a coolant temperature sensor 10, a lean/rich indicative signal for air/fuel ratio outputted from an 02 sensor 11, an intake-air flow indicative signal of an intake-air flow sensor 12, an ON/OFF signal of an air conditioner switch 13, a vehicle-speed indicative signal outputted from a vehicle-speed sensor 14, an ON/OFF signal of an idle switch 15, a throttle position indicative signal autputted from a throttle position sensor 16, an ONIOFF signal of a neutral switch 17, an engine-speed indicative signal outputted from an engine-speed sensor 18, and so forth. These input data are processed by means of the CPU 3 and temporarily stored in the RAM 5 to be used for the operations of control amounts.

That is, the CPU 3 carries out various operations of control amounts, such as a fuel-injection pulse width and an ignition timing, on the basis of the respective data stored in the RAM 5, and outputs a control signal corresponding to each control amount from the output interface 7 to the drive circuit 9 at a predetermined timing.

The drive circuit 9 is connected to a canister control unit 19 for controlling a canister purge amount, a 7 throttle actuator 20 for controlling a throttle position, an idle control actuator 21 for controlling an idle speed, an ignition coil 22 for applying a high voltage to a spark plug, an injector 23 for injecting a fuel, and so forth- The drive circuit 9 is driven by the control signals from the output interface 7 so that the engine is controlled to be the optimum condition for each operating range.

The drive circuit 9 is also connected to a self-diagnosing lamp unit 24 for indicating a trouble code corresponding to a fault site read out of the ROM 4 by, e.g., suitably turning a plurality of lamps on or for flashing the lamps on and off, when the abnormality in the system is detected by a self-diagnosing function.

A part of the RAM 5 comprises a backup RAM, to which power is supplied from a battery VB via the constant-voltage supply circuit 8 for storing data even after the power supply of the system is turned off, and stores therein the learned values obtained by the learning control, the trouble codes correspondIng to the fault sites detected by the self- diagnosing function, and so forth- The basic construction of the select monitor A other than the 'expanded functions will be described below.

The select monitor A is disposed in a dealer's service factory or the like. The select monitor A includes a main control part 35 of a microcomputer, a power supply circuit 36 for supplying constant voltages to the respective parts. The main control part 35 Is connected tothe detachably mounted memory cassette 60, which can be replaced from the outside, via a cassette connector 37.

The power supply circuit 36 can supply power from the battery VB of the vehicle B via a cigar lighter cable or f rom a general alternating -current power supply via an AC/DC adapter. Alternatively, the power supply circuit 36 can include a power supply to supply power. Thus, the power supply circuit 36 can correspond to three types of power supplies.

The main control part 35 comprises: a CPU 40 serving 8 as a main processor; a ROM 41 in which a system program, data of the menu and various messages indicated on the display 30 and so forth are stored; a RAM 42 comprising a work RAM for storing work data, a video RAM and so forth; a diaginterface 43 which is a connecting interface to the on-vehicle electronic controller C; an input/display interface 44 for processing the turning-on (or flashing) of the light emitting diodes of the indicator part 31, a key operation indicative signal from the keyboard 32, and a display signal to the display 30; and a ROM 61 provided in the memory cassette 60, wherein CPU 40, ROM 41, RAM 42, dlaginterface 43, Input/display interface 44 and ROM 61 are connected to each other via bus lines. As shown in FIG. 10, the input/display interface 44 is provided with a key lighting driving circuit 44a for turning lighting elements serving as back lights of the keyboard 32 on.

In this preferred embodiment, the lighting elements serving as back lights of the keyboard 32 are green light emitting elements LEDG and red light emitting elements LEDR.

A pair of green and red.light emitting elements LEDG, LEDR are mounted in each of keys, and are designed to be selectively turned on by means of the key lighting driving circuit 44a.

The anodes of each pair of light emitting diodes LEDG, LEDR are connected to a constantvoltage power supply VCC from the power supply circuit 36, and the cathodes thereof are connected to the collectors of emitter-grounded NPN-type transistors TRG, TRR via resistors RCG, RCR, respectively. The bases of the respective resistors TRG, TRR are connected to a latch RC via resistors RBG, RBR, respectively.

In FIG. 10, two latches RC are used, and six pairs of tiansistors TRG, TRR for driving six pairs of light emitting diodes LEDG, LEDR corresponding to six keys are controlled by a single latch RC. The respective latches RC are connected to bus lines of the microcomputer forming the main control unit 35. When the key function is changed, the lighting of 9 the corresponding key is switched between the green light emitting diode LEDG and the red light emitting diode LEDR.

The dlaginterface 43 generally comprises a field programmable gate array (FPGA) wherein the logic function can 5 be on-board reprogrammed by supplying a design information. By this FPGA, it is possible to realize a hardware for an 1/0 interface which can be connected to any on-vehicle electronic controllers C, and a hardware for a serial communication interface which can be adapted to any communication protocols of various on-vehicle electronic controllers C, regardless of the type of vehicle or vehicle manufacturer.

The memory cassette 60 is designed so that the select monitor A can be used for general purposes, regardless of the differences in diagnosed item, the type of vehicle and the communication protocol. The memory cassette 60 stores a diagnosis processing program corresponding to the onvehicle electronic controller C, design data such as logic information for reprogramming the FPGA so as to be adapted to the communication protocol of the on-vehicle electronic controller C, and so forth.

When the diagnosis is carried out, the memory cassette 60 is set wherein the diagnosis processing program corresponding to the on-vehicle electronic controller C (the EM 2 for controlling the engine in this preferred embodiment), the design data for reprogramming the FPGA of the diaginterface 43 and so forth are stored. Then, the design data of the FPGA stored in the ROM 61 are transferred while initializing the select monitor A, and the FPGA is reprogrammed so that the I/0 connection and the serial communication with the on-vehicle electronic controller C can be carried out.

As mentioned above, the diagnosis with the select monitor A is carried out using the menu facility of the basic hierarchical structure, and it is possible to easily carry out the diagnosis by selecting the menu without the need of high-grade knowledge and experience. In this case, since the number of the keys of the keyboard 32 of the select monitor A is few (12 in this preferred embodiment), a plurality of functions are assigned to the same key, and the diagnosing operation is carried out by operating the key while selecting the functional mode of the key.

For that reason, in the select monitor A, the lighting state of the back light is changed so as to correspond to the change of the key functional mode, by key lighting means, key function switching means and key lighting control means according to the present invention. Thus, it is possible to easily distinguish the current key functional mode while preventing the display area of diagnosing information from decreasing by indicating the key functional mode on the display 30.

Referring to the f lowcharts of FIGS. 2 and 3, the processing for the key lighting of the select monitor A will be described below.

First, when the select monitor A, on which the memory cassette 60 adapted to the ECU 2 of the vehicle B to be diagnosed is mounted, is connected to the EW 2 via the diagcable 34, and when the power supply switch is turned on, the CPU for controlling the system of the select monitor A is reset and the processing shown in FIGS. 2 and 3 starts.

In this processing, at step S101, the initializing is carried out, which includes the clearing of flags, the functional mode setting for the respective keys of the keyboard 32, the data setting to the latch RC for lighting the back lights of the keys in green in accordance with the functional modes (the data setting for turning the transistor TRG of the key lighting driving circuit on and for turning the transistor TRR off, i.e., the data setting for turning the light emitting diode LEDG on and for turning the light emitting diode LEDR off), and so forth. Then, at step S102, the screen data of the select monitor menu as the initial menu are transferred from the memory table of the menu screen data to the video RAM, and the select monitor menu is indicated on the display 30 as shown in FIG. 4.

In FIG. 4, the select monitor menu is at the top of 11 the hierarchy and list seven items including the expanded functions, and the contents registered to the function keys 53 through 56 of Fl through F4 are displayed with the menu.

For example, a command for returning to the initial menu screen, a command for returning to an upper hierarchy by one, a command for resetting, and an end command are'assigned to the function keys 53:through 56 of Fl through F4, so that it is possible to easily move to a desired screen by pressing the appropriate function key.

Then, the operator moves a cursor upwards or downwards to a desired menu item to inversely display the item using the direction key 45 or 46 ( " T "' or " 1.' key) while viewing the menu screen. When the operator presses the YES key 51, the selection is made to display the lower hierarchy.

that is, after the select monitor menu is displayed at step S102, the routine.goes to step S103 for waiting next keystroke. When a 'keystroke is made, the routine goes to step S104 wherein the coding of key for converting the keystroke into a code referring to the key code table is carried out. Then, at step S105, it is determined whether the keystroke of the shift key 49 is carried out an the basis of the key code.

When it is determined at step S105 that the keystroke of the shift key 49 Is not carried out, the routine goes to step S106 wherein it is determined whether the keystroke of the selection. key 50 is carried out- When the keystroke of the selection key 50 is not carried out, the routine goes to step S107 wherein it is determined whether the keystroke of any one of the direction keys 45, 46, 47 and 48 is carried out. When the keystroke of any one of the direction keys 45, 46, 47 and 48 is carried out, the routine goes to step S108 wherein the key function switching flag Flag is referred.

As described later, the key function switching flag Flag indicates that the functional mode of the key is changed from the initial mode (which will be hereinafter referred to as a '@usual mode") when it is set to be 1. Therefore, when the routine is executed for the first time or when the key 12 function is not changed, the routine goes from step S108 to step S109 wherein the processing for the key function is carried out, and then, the routine returns to step S103.

In the key function processing in the usual mode at step S109, the cursor is moved upwards by one line when the direction key 45 ("T" key) is depressed, and the cursor is moved downwards by one line when the direction key 46 ("1" key) is depressed. In addition, when the direction key 47 or 48 or key) is depressed, the keystroke is invalidated and the routine returns to step 103.

When the routine returns from step S109 to step S103 and when the next keystroke is carried out, the keystroke is coded at step S104. When none of the shift key 49, the selection key 50 and direction keys 45, 46, 47 and 48 are not depressed, the routine goes to step S112 via steps S105, S106 and S107, and it is determined whether the keystroke of the YES key 51 is carried out.

When the keystroke of the YES key 51 is not carried out, the routine returns from step S112 to step S103, and when the keystroke of the YES key 51 is carried out, the routine goes from step S112 to step S113 wherein the processing of the selected item is carried out, and then, the routine returns to step S103. This processing is a processing for skipping, to the menu screen of the item selected with the cursor as far as it is performed in the usual mode. For example, the cursor is disposed at the second Item "2. Diagnosis for Vehicle System" In the select monitor menu screen as shown in FIG. 4, and when the YES key 51 is depressed, the display data of the vehicle diagnosing menu is selected from the memory table to be transferred to the video RAM to open the vehicle diagnosing menu on the display 30.

After, the 'Vehicle diagnosing menu which is a hierarchy under the select monitor menu is indicated on the display 30 (see FIG. 5), the keeptroke is determined in the same manner from step S103 to step S112. When it is determined at step S112 that the keystroke of the YES key 51 13 is carried out, i.e., when the YES key 51 is depressed while the cursor is disposed at the item "1. Data Display/Memory" in the vehicle diagnosing menu as shown in FIG. 5, the routine goes to step S113 wherein the display data of the data display/memory menu is selected from the memory table and the data display/memory menu shown in FIG. 6 is indicated on the display 30. Furthermore, right after opening next menu, the cursor is disposed at the uppermost item of the menu.

Similarly, when the cursor is disposed at the fifth menu item "S. Graph Display (lch)" as shown in FIG. 6 and when the YES key 51 is depressed, the graph display setting menu is opened on the display 30. When the engine-speed graph is selected from the items of the graph display setting menu, the respective items for setting the engine-speed graph is displayed.

In this preferred embodiment, different functions are assigned to the direction keys 45, 46, 47 and 48, and the functional modes of the direction keys 45, 46, 47 and 48 are, changed. In particular, when the shift key 49 is depressed, the functional mode of the key is switched. That is, when the shift key 49 is depressed, the keystroke of this shift key 49 is detected at steps 5103, S104 and S105, and the routine goes from step S105 to step S114. When it is determined at step S114 that the value of the key function switching flag Flag is Flag=O, the routine goes to step S115 wherein the output data to the latch RC is changed so that the light emitting diodes LEDG serving as the back lights.for the direction keys 45, 46, 47 and 48 are turned off and the light emitting diodes LEDR are turned on. Then, the routine goes to step S116 wherein the key function switching flag Flag is set (Flag.-1), and the routine returns to step S103- Thus, the 11.9htind serving as the back light for the direction keys 45, 46, 47 and 48 are switched from green in the usual mode to red in the special made, so that it is possible for the operator to easily recognize that the functional modes of the keys are changed for the subsequent 14 key operations, thereby to prevent misoperation.

In this preferred embodiment, while the lighting color of the back light for the corresponding key has been changed from green to red, other colors may be used, e.g., it may be changed from blue to yellow. Alternatively, the back light for the corresponding key may be flashed on and off. in addition, the luminance of the back light for the corresponding key may be increased. Moreover, only the back light for the corresponding key may be turned on, and the back lights for the other keys may be turned off.

When the key function is changed while the cursor is at the Item "Minimum Incorporation Speed ---- rpm" on the engine-speed graph setting screen shown in FIG. 7(a), the cursor then appears at the lowest numerical position next to the display of "rpm" to wait for the numeric input, as shown in FIG. 7(b). When any one of the direction keys 45, 46, 47 and 48 is operated while the numeric input is prompted, the routine goes from step S107 to step S108 via steps S103, S104, S105, 5106 and S107, and it is determined at step S108 whether the direction keystroke is carried out.

As mentioned.above, the key function switching flag Flag Is referred at step S108. When the key functional mode is changed to Flag=l, the routine goes from step S108 to step S110 wherein the switching processing of the key function is carried out. Then, the various processings of step S111 are carried out, and the routine returns to step S103.

In the key function switching processing from step 5110 through S111, the function of the direction key 45 is changed from the function for the upward movement of the cursor in the usual mode, to the function for increasing the numeric so as to be and the function of the direction key 46 is changed from the function for the downward movement of the cursor in the usual mode, to the function for decreasing the numeric so as to be 9-8-7 ---16-5-14-3-2-1-0. In addition, as shown in FIG. 7(c), the shift of the numerical position to be input can be carried out by means of the direction keys 47 and 48. Thus, the is desired numeric values of 0 through 9 can be input to all the numerical positions by means of the direction keys 45 through 48. Then, the minimum incorporation speed is set by inputting the numeric

value using the direction keys 45 and 46 and by shifting using the direction keys 47 and 48. Then, when the selection key 50 is depressed, the routine goes from step S106 wherein it is determined whether the keystroke of the selection key is carried out, to step 5117. At step S117, the value of the key function switching flag Flag is referred.

When it is determined at step S117 that it is in the usual mode wherein Flag=O, the routine goes to step S118 wherein the processing corresponding to the operated input is carried out, and the routine returns to step S103. On the other hand, when it is determined at step S117 that Flag=1 wherein the functional mode of the key is changed, the routine goes to step S119 wherein the set input values such as- the minimum incorporation speed set using the direction keys 45, 46, 47 and 48 are stored in the memory. Then, the routine goes to step S120 wherein the output data to the latch RC is returned to the value in the usual mode. Then, the routine goes to step S121 wherein the key function switching flag Flag is cleared (Flag-0), and the routine returns to step S103.

Thus, the light emitting diodes LEDR serving as the back lights for the direction keys 45, 46, 47 and 48 are turned off and the light emitting diodes LEDG are turned on, and the lighting for the back lights of the direction keys 45, 46, 47 and 48 is switched from red to green in the usual mode.

In this case, the shif t key 47 can be substituted for the selection key 50 to store the setting Input value in the memory and to return the functional mode of the key to the usual mode. That is, when Flag=1 at step S114, i.e., when the shift key 49 is depressed again after the functions of the direction keys 45, 46, 47 and 48 are changed by the 16 keystroke of the shift key 49, the routine goes from step S114 to step S119 wherein the output data to the latch RC is returned to the data for turning the light emitting diodes LEDR serving as the back lights for the direction keys 45, 46, 47 and 48 off and for turning the light emitting diodes LEDG on. Then, when the lighting for the back lights of the direction keys 45, 46, 47 and 48 is switched f ram red to green in the usual mode, the routine goes to step S116 wherein the key function switching flag Flag is cleared (Flag"-O), and the routine returns to step S103.

When the functional modes of the direction keys 45, 46, 47 and 48 are returned to the usual mode, the operation of the direction key 46 can move the cursor downwards from the item of the minimum incorporation speed on the display screen for setting the engine-speed graph shown in FIG. 7(a). Then, it is possible to change the key functional mode by operating the shift key 49 again, and it is possible to input a numeric value to the item "Maximum Incorporation Speed ----rpm" to fix the set input value by means of the selection key 50 or the shift key. 49. Moreover, it is possible to repeat the similar procedures to input numeric values to the items "Time-Axis Full Scale" and "Sample Cycle ---ms" to fix the set values.

Thus, when the engine-speed graph setting is completed and when the YES key 51 is depressed, the routine goes from step S103 to step S112 via steps S104, S105, S106 and S107. At step S112, the keystroke of the YES is detected, and the routine goes to step S113 wherein the processing of the selected item is carried out. In this processing, the enginespeed data are read for a predetermined period of time after starting the data communication with the ECU 2, and the read data are processed to make a graph. As a result oi this processing, the engine-speed graph shown in FIG. 8 appears on the display 30.

Thereafter, in a case where another menu item is carried out, the display of the engine-speed graph is finished by depressing, e.g., the F4 function key 56, and a 17 desired item is selected in the similar manner. In addition, in order to return to the vehicle diagnosing menu of the last hierarchy, the F2 function key 53 is depressed, and in order to return to the initial select monitor menu, the Fl function key 53 is depressed. Thus, it is possible to continue the diagnosis by selecting a desired menu item in the similar manner.

While the presently preferred embodiments of the present invention have been shown and described, it is to be understood that these disclosures are for the purpose of illustration and that various changes and modification may be made without departing from the scope of the invention as set forth in the appended claims.

1

Claims

18 CLAIMS:

1. Diagnostic apparatus selectively conneCted to an electronic controller mounted on an automotive vehicle and having keys for the request to read data out of the electronic controller, said diagnosing apparatus comprising:

key lighting means for lighting said key as a back light; key function switching means for switching a function of said key in response to a selected input, said key being previously set so as to have a plurality of functions; and key lighting control means for changing a lighting state of the corresponding key lighted by said key lighting means when said function of said key is switched by said key function switching means.

2. Diagnostic apparatus as set forth in claim1, wherein said key lighting control means changes said lighting state of the corresponding key by a Lighting color or brightness.

3. Diagnostic apparatus substantially as hereinbefore described with reference to any of the accompanying drawings.