Vehicle diagnosis system

• US 5,479,347 A
• Filed: 06/14/1994
• Issued: 12/26/1995
• Est. Priority Date: 06/17/1993
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Iwai, Akihito, Takaba, Katsumi, Oguro, Hirokazu
• Primary Examiner(s): Chilcot, Jr., Richard B.
• Assistant Examiner(s): Noori, Max H.
• Application Number:
  US08/260,408
• Time in Patent Office: 560 Days
• Field of Search: 73/118.1, 364/424.04, 364/424.03, 340/438, 340/439
• US Class Current: 701/35
• CPC Class Codes: G06F 11/2294 by remote test

Abstract

In a vehicle diagnosis system in which a diagnosis unit is connected to a control unit, the control unit determines whether or not there is a code read request from the diagnosis unit. When there is the request, it further determines whether or not code erase is in execution. When code erase is not in execution, an abnormality code stored in the standby RAM region of its CPU is searched for and the result is transmitted to the diagnosis unit. When code erase is in execution, on the other hand, the data after code erase (no abnormality code) is transmitted to the diagnosis unit. Thus, during code erase operation, the abnormality data before erase is prevented from being transmitted to the diagnosis unit.

Further, in case of a RAM value read request is made from a main CPU to other CPU in the controller, it is checked whether a requested address value from the main CPU to the other CPU agrees with the address value transmitted from the other CPU to the main CPU. When the address values agree, the flag XA4ANS is set. After a prescribed interval from this flag setting, the RAM value corresponding to the requested address are responsively sent out to the diagnosis unit. Therefore, transmission of erroneous information to the diagnosis unit can be prevented without fail.

Claims

1. A vehicle diagnostic system comprising:

a controller installed in a vehicle for detecting various abnormalities and storing information about such abnormalities in storage means thereof, and

a diagnostic unit connectable to said controller and having read requesting means to request a read-out of the abnormality information stored in said storage means and erase request means to request erasure of the abnormality information stored in said storage means, wherein said controller is provided with;

abnormality information erasing means for erasing the abnormality information stored in said storage means in response to an erase request of the abnormality information from said erase requesting means;

erase condition detecting means for detecting whether the abnormality information is being erased; and

abnormality information transmitting means for transmitting the abnormality information stored in said storage means to said diagnostic unit in response to a read request of the abnormality information from said read requesting means when said erase condition detecting means detects no erase condition, for preventing erroneous output of pre-erasure abnormality information from said controller to said diagnostic device when said erase condition detecting means detects erase an condition, and during erasing of the abnormality information by said abnormality information erasing means, for transmitting predetermined information indicative of no abnormality.

2. A vehicle diagnostic system comprising:

storage means for detecting various abnormalities of a vehicle and for storing abnormality information;

abnormality information erasing means for erasing abnormality information stored in said storage means in response to an erase signal from diagnosis means;

erase condition detecting means for detecting whether the abnormality information is being erased;

erase status detecting means for detecting whether erasure of abnormality information is in execution by said abnormality information erasing means and for preventing erroneous output of pre-erasure abnormality information from said storage means when a read command is input externally during erasure of abnormality information from said storage means; and

abnormality information output means for outputting abnormality information after erasure, when said erase status detecting means detects that erasure of abnormality information is in execution, in response to a read signal applied from said diagnosis means, and for outputting abnormality information stored in said storage means when said erase status detecting means detects that erasure of abnormality information is not in execution.

3. A vehicle diagnostic system as claimed in claim 2, wherein said erase status detecting means includes:

measuring means which measures time from receiving of the erase signal from said diagnostic means; and

erase status determining means which determines whether or not erase of abnormality information is in execution, in reference to the measured time.

4. A vehicle diagnostic system as claimed in claim 3, wherein said measuring means includes:

battery voltage detecting means which detects battery voltage;

low voltage detecting means which detects whether or not said battery voltage is up to a prescribed value; and

clearing means which clears the measured time when said low voltage detecting device detects that said battery voltage is up to the prescribed voltage.

5. A vehicle diagnostic system comprising:

a plurality of CPUs including other CPUs and a main CPU which controls vehicle operation, detects various abnormalities and conducts information communication with an external device;

a plurality of storage devices provided in said plurality of CPUs for storing abnormality information detected by the individual ones of the plurality of CPUs, wherein said main CPU includes;

erase instruction output means for outputting an abnormality information erase instruction to the other CPUs in response to an erase signal from said external device;

erase instruction output means for outputting an abnormality information erase instruction to the other CPUs when no erase signal from said external device is received, and for outputting predetermined data to the other CPUs when an erase signal has been received;

erase status detecting means for detecting whether an erase signal has been received.

6. A vehicle diagnostic system as claimed in claim 5, wherein said storage device includes:

DMA means which transmits information individually stored through direct memory access to the other storage device.

7. A vehicle diagnostic system comprising:

a controller including a plurality of control means, each of said control means having a CPU for control of vehicle operation on the basis of vehicle information and a RAM storing control information, said control means being connected so as to permit transmission and receiving of data through direct memory access; and

a diagnostic unit connectable to said controller and including;

read requesting means for requesting the reading of control information stored at a desired address of said RAM;

read request address writing means for writing said desired address corresponding to said read request of control information from said read requesting means into a first direct memory access region;

read information writing means for writing control information and an address value corresponding to said desired address written in said first direct memory access region into a second direct memory access region; and

responding means for sending control information written in said second direct memory access region to said diagnostic unit as a response when there is agreement between the address value in said second direct memory access region and said desired address value and upon lapse of a prescribed period of time after the agreement.

8. A vehicle diagnostic system comprising:

a main CPU having a RAM for storing information, said main CPU performing data communication with an external diagnosis unit, and

at least one other CPU having a RAM for storing control information, said at least one other CPU calculating an amount of vehicle control in accordance with a prescribed control program, wherein said main CPU includes;

instruction signal receiving means for receiving an instruction signal for reading out desired control information in the control information stored in the RAM of said at least one other CPU;

read requesting means for causing a first storage area of said at least one other CPU to store a requested address corresponding to said desired control information in response to the request of said instruction signal;

a second storage area for storing said requested address responded by said at least one other CPU;

a third storage area for storing requested address data corresponding to the requested address responded by said at least one other;

response completion detecting means for detecting a completion of response signal from the at least one other CPU in response to agreement between the value stored in the second storage area and said requested address; and

desired control information transmitting means for transmitting the requested address data stored in said third storage area to said external diagnosis unit in response to detection of said completion of response signal, and for transmitting predetermined data to prevent erroneous output to said external diagnosis unit when no completion of response signal is detected by said response completion detecting means;

wherein each said at least one other CPU includes;

requested address data reading means for reading out the requested address data corresponding to said requested address stored in said first storage area from said RAM; and

desired control information responding means for causing said third storage area to store said requested address data and then for causing said second storage area to store said address.

9. A vehicle diagnosis system as claimed in claim 8, wherein said response completion detecting means includes:

time measuring means which measures lapse of time from agreement between the value stored in said second storage area and said requested address; and

response completion determining means which determines the lapse of a prescribed period of time to correspond to completion of response to said other CPU.

10. A vehicle diagnosis system as claimed in claim 8, wherein data communication between said RAM of said main CPU and said RAM of said other CPU is performed through direct memory access.

11. A vehicle diagnostic device as claimed in claim 8, wherein said instruction signal receiving means includes:

abnormality detecting means which determines non-agreement of said instruction signal with a prescribed format to mean a communication abnormality.