Diagnosis system for a motor vehicle

• US 5,005,129 A
• Filed: 02/21/1989
• Issued: 04/02/1991
• Est. Priority Date: 02/29/1988
• Status: Expired due to Term

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Sakamoto, Masanori, Kobayashi, Tomoya, Abe, Kunihiro
• Primary Examiner(s): Gruber, Felix D.
• Application Number:
  US07/314,647
• Time in Patent Office: 770 Days
• Field of Search: 364/431.01, 364/424.03, 364/551.01, 73/116, 73/117.2, 73/117.3, 73/119 R, 73/119 A
• US Class Current: 701/31
• 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: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A system for diagnosing a motor vehicle has a diagnosis device including a computer having a central processing unit and a ROM. The ROM stores a plurality of programs for diagnosing an electronic control system for controlling an engine. The electronic control system has a self-diagnosis function and a nonvolatile memory for storing trouble data as a result of the self-dignosis. A communication system is provided in the diagnosis device for supplying a trouble check signal to the electronic control system. In response to the trouble check signal, the electronic control system derives the trouble data from the nonvolatile memory and sends the trouble data to the diagnosis device.

Claims

1. A diagnosis system for diagnosing an electronic control system for a vehicle, the electronic control system comprising sensing means for detecting operation conditions of the vehicle, and a first control unit responsive to the operation conditions for providing control signals for controlling the vehicle, the diagnosis system comprising a diagnosis device with a keyboard for inputting a code, a second control unit responsive to the code for diagnosing the electronic control system, display means for displaying diagnosis data diagnosed by the second control unit, and connecting means electrically connecting the diagnosis device to the electronic control system,

said first control unit comprising a programmed control system comprising self-diagnosis means for checking trouble in the electronic control system and for storing the trouble as trouble data and designation means for designating one of a plurality of test modes for the trouble data to said self-diagnosis means;

said second control unit comprising a programmed control system comprising;

interpreting means for interpreting the code inputted from the keyboard as a first specific code for checking the trouble data and for producing a first signal;

communication means for applying a first command signal to the self-diagnosis means in response to the first signal for feeding the trouble data from the self-diagnosis means under a test mode designated by the designation means;

means for processing the trouble data fed from the self-diagnosis means by the communication means to display the trouble data on the display means;

said interpreting means for interpreting the code inputted from the keyboard as a second specific code for changing the test mode and for producing a second signal;

said communication means being responsive to the second signal for applying a second command signal to the designation means; and

said designation means being responsive to the second command signal for changing the test mode of the self-diagnosis means.

2. The diagnosis system according to claim 1, wherein

said processing means comprises conversion means for converting the trouble data fed from the self-diagnosis means by the communication means into a corresponding trouble code and abbreviation to indicate the trouble mode and the abbreviation on the display means.

3. A diagnosis system for diagnosing an electronic control system for a vehicle, the electronic control system comprising sensing means for detecting operation conditions of the vehicle, and a first control unit responsive to the operation conditions for providing control signals for controlling the vehicle, the diagnosis system comprising a diagnosis device with a keyboard for inputting a code, a second control unit responsive to the input code for diagnosing the electronic control system, display means for displaying diagnosis data diagnosed by the second control unit, and connecting means electrically connecting the diagnosis device to the electronic control system,

the first control unit comprising a programmed control system comprising self-diagnosis means for checking trouble in the electronic control system and for storing the trouble as trouble data and designation means for designating one of a plurality of test modes for the trouble data to said self-diagnosis means;

said second control unit comprising a programmed control system comprising;

first determining means for determining whether the input code is a first specific code for changing the test mode;

second determining means for determining whether the input code is a second specific code for checking the trouble data when the first specific code for changing the test mode is not determined by said first determining means;

first applying means for applying a test mode demand signal to the electronic control system for demanding a present test mode of the self-diagnosis means when the second specific code for checking the trouble data is determined by said second determining means;

first receiving means for receiving the present test mode demanded by said applying means from the designation means;

third determining means for determining the kind of the present test mode received by said first receiving means;

second applying means responsive to the kind of the present test mode for applying a trouble data demand signal to the self-diagnosis means for demanding the trouble data;

second receiving means for receiving the trouble data demanded by said second applying means from the electronic control system;

retrieving means for retrieving a trouble code and abbreviation corresponding to the trouble data received by said second receiving means based on the present test mode determined by said third determining means;

displaying means for displaying the trouble code and the abbreviation on the display means; and

third applying means for applying a test mode change signal to the designation means for changing the designation of the test mode the self-diagnosis means when the first specific code for changing the test mode is determined by said first determining means.