Diagnosis apparatus for vehicle control system

• US 5,553,488 A
• Filed: 11/06/1995
• Issued: 09/10/1996
• Est. Priority Date: 07/30/1993
• Status: Expired due to Term

• Current Assignee: Ibaraki Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ishii, Satoshi, Akatsuka, Takao
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US08/554,205
• Time in Patent Office: 309 Days
• Field of Search: 73/116, 73/117.2, 73/117.3, 364/424.01
• US Class Current: 73/114.61
• CPC Class Codes: B60T 2270/415 Short-circuit, open circuit failure
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A diagnosing apparatus for use in a vehicle is disclosed. A microcomputer operates according to either a first mode or a second mode. The second mode being used for the diagnosis requiring a higher precision than the diagnosis according to the first mode. A first program for detecting the malfunction of a control system and a second program having a higher detection precision than the first program is stored in a memory. The operation mode of the microcomputer is selected in accordance with an extent of the malfunction. The diagnosis according to the first program and the second program are executed when the first mode and the second mode are selected, respectively. An operation status of the control system is detected by sensors the diagnosis is performed in the second mode. The diagnosis mode is forcibly returned to the first mode from the second mode when the status detected by the detecting means matches with a predetermined conditions.

Claims

1. A diagnosing apparatus for use in a control system of a vehicle for controlling actuators based on signals from sensors transferred to a microcomputer to diagnose a malfunction of said control system by means of said microcomputer, wherein said microcomputer operates in a selected operation mode from a group consisting of a first mode and a second mode, said second mode being used for the diagnosis requiring a higher precision than the diagnosis according to the first mode, said apparatus comprising:

first memory means for storing a first program for detecting the malfunction of said control system and a second program having a higher detection precision than said first program;

first selecting means for selecting the operation mode of the microcomputer in accordance with an extent of the malfunction of the control system;

executing means for executing the diagnosis according to the first program when the selecting means selects the first mode, and executing diagnosis according to the second program when the selecting means switches the operation mode from the first mode to the second mode;

second memory means for storing a plurality of condition patterns of said control system for returning the operation mode of the microcomputer to the first mode from the second mode;

second selecting means for selecting a specific condition pattern among said plurality of condition patterns stored in the second memory means;

setting means for setting a condition of said control system based on the specific condition pattern selected by the second selecting means;

detecting means for detecting a status of said control system when the diagnosis is performed in the second mode; and

return means for forcibly returning said diagnosis mode to the first mode from the second mode when the status detected by the detecting means matches with the conditions set by the setting means when the second mode is carried out.

2. The diagnosing apparatus as set forth in claim 1 further including an external diagnosing unit, provided separate from said control system, said external diagnosing unit being coupled to said control system to exchange data with said control system when the diagnosis based on said second program is executed.

3. The diagnosing apparatus according to claim 2, wherein said external diagnosing unit includes a switch operable to switch said first mode to said second mode and operable to set said condition of said control system for returning the operation mode from the second mode to the first mode.

4. The diagnosing apparatus according to claim 3, wherein said setting means sets the condition of the control system based on data transmitted from the external diagnosing unit after the switch thereof is manipulated.

5. The diagnosing apparatus according to claim 3, wherein said condition of said control system for returning said second mode to said first mode is preset by said setting means when the vehicle is manufactured.

6. The diagnosing apparatus according to claim 1, wherein said vehicle includes an engine and an ignition switch operable to selectively activate and deactivate the engine, and wherein said detecting means constitutes a part of said control system and includes count means for counting a number of times of manipulation of the ignition switch.

7. The diagnosing apparatus according to claim 1, wherein said detecting means includes a sensor for detecting a change in operational status of said vehicle.

8. The diagnosing apparatus according to claim 7, wherein said sensor comprises a vehicle speed sensor for detecting a speed of said vehicle.

9. The diagnosing apparatus according to claim 1, wherein said setting means includes:

a connector coupled to said control system and having a plurality of external terminals, one of said external terminals being grounded and at least two of said external terminals being short circuited, wherein a plural types of signals is input to said control system in accordance with combinations of said short-circuited external terminals;

status memory means for storing a data indicative of plurality of conditions of the control system for returning the second mode to the first mode, said plurality of statuses stored in corresponding to input signals associated with short-circuiting of said external terminals; and

second selecting means for selecting one of said plurality of statuses based on the input signal associated with short-circuiting of said external terminals.

10. The diagnosing apparatus according to claim 1, wherein said setting means includes:

a connector coupled to said control system and having a plurality of external terminals, one of said external terminals being grounded and at least two of said external terminals being short circuited, wherein a plural types of signals is input to said control system in accordance with combinations of said short-circuited external terminals;

status memory means for storing a data indicative of plurality of conditions of the control system for returning the second mode to the first mode, said plurality of statuses stored in corresponding to input signals associated with short-circuiting of said external terminals; and

second selecting means for selecting one of said plurality of statuses based on the input signal associated with short-circuiting of said external terminals.

11. A diagnosing apparatus including an ignition switch for selectively energizing and deenergizing an engine and sensors attached to a vehicle, said apparatus being for use in a control system for the vehicle for controlling actuators based on signals from the sensors transferred to a microcomputer to diagnose a malfunction of said control system by means of said microcomputer, wherein said microcomputer operates in a selected operation mode from a group consisting of a first mode and a second mode, said second mode being used for the diagnosis requiring a higher precision than the diagnosis according to the first mode, said apparatus comprising:

memory means for storing a first program for detecting the malfunction of said control system and a second program having a higher detection precision than said first program;

selecting means for switching the operation mode from the first mode to the second mode;

executing means for executing the diagnosis according to the first program when the selecting means selects the first mode, and executing diagnosis according to the second program when the selecting means switches the operation mode from the first mode to the second mode;

setting means for setting an operation number of the ignition switch as a condition of said control system to return the operation mode to the first mode from the second mode, wherein the operation number represents the number of times the ignition switch is operated;

counting means for counting the operation number of the ignition switch when the diagnosis is performed by the second mode; and

return means for forcibly returning said diagnosis mode to the first mode from the second mode when the operation number of the ignition switch matches the number set by the setting means when the second mode is carried out.

12. The diagnosing apparatus according to claim 11, further including an external diagnosing unit, provided separate from said control system, said external diagnosing unit being coupled to said control system to exchange data with said control system when the diagnosis based on said second program is executed.

13. The diagnosing apparatus according to claim 12, wherein said external diagnosing unit includes a switch operable to switch said first mode to said second mode and operable to set said condition of said control system for returning the operation mode from the second mode to the first mode.

14. The diagnosing apparatus according to claim 13, wherein said setting means sets the condition of the control system based on data transmitted from the external diagnosing unit after the switch thereof is manipulated.

15. The diagnosing apparatus according to claim 13, wherein said condition of said control system for returning said second mode to said first mode is preset by said setting means when the vehicle is manufactured.

16. The diagnosing apparatus according to claim 11, wherein said setting means includes:

a connector coupled to said control system and having a plurality of external terminals, one of said external terminals being grounded and at least two of said external terminals being short circuited, wherein a plural types of signals is input to said control system in accordance with combinations of said short-circuited external terminals;

status memory means for storing a data indicative of plurality of conditions of the control system for returning the second mode to the first mode, said plurality of statuses stored in corresponding to input signals associated with short-circuiting of said external terminals; and

second selecting means for selecting one of said plurality of statuses based on the input signal associated with short-circuiting of said external terminals.

17. A diagnosing apparatus including an ignition switch for energizing and deenergizing an engine and sensors attached to a vehicle, said apparatus being for use in a control system for the vehicle for controlling actuators based on signals from the sensors transferred to a microcomputer to diagnose a malfunction of said control system by means of said microcomputer, wherein said microcomputer operates in a selected operation mode from a group consisting of a first mode and a second mode, said second mode being used for the diagnosis requiring a higher precision than the diagnosis according to the first mode, said apparatus comprising:

memory means for storing a first program which detects the malfunction of said control system and a second program having a higher detection precision than said first program;

determining means for determining the operation mode of the control system;

executing means for executing the diagnosis according to the first program when the determining means determines the first mode, and executing diagnosis according to the second program when the operation mode is switched from the first mode to the second mode;

an external diagnosis device apart from the control system, said external device being arranged to be selectively connected with and disconnected from the control system, wherein said external device and said control system outputting data signal to each other;

mode switching means for switching the operation mode from the first mode to the second mode based on the data signal provided by the external device;

setting means for setting an operation number of the ignition switch as a condition of said control system based on the data signal provided by the external device so as to return the operation mode to the first mode from the second mode, wherein the operation number represents the number of times the ignition switch is operated;

counting means for counting the operation number of the ignition switch when the diagnosis is performed by the second mode; and

return means for forcibly returning said diagnosis mode to the first mode from the second mode when the operation number of the ignition switch matches the number set by the setting means when the second mode is carried out.

18. The diagnosing apparatus according to claim 17, wherein said external diagnosing unit includes a switch operable to switch said first mode to said second mode and operable to set said condition of said control system for returning the operation mode from the second mode to the first mode.

19. The diagnosing apparatus according to claim 18, wherein said setting means sets the condition of the control system based on data transmitted from the external diagnosing unit after the switch thereof is manipulated.

20. The diagnosing apparatus according to claim 18, wherein said condition of said control system for returning said second mode to said first mode is preset by said setting means when the vehicle is manufactured.