Abstract: In a vehicle diagnosis information communication system, electric power is supplied from a battery to a vehicle control computer mounted on the vehicle during a period of vehicle operation, while the electric power is supplied to a radio communication unit mounted on the vehicle irrespective of the vehicle operation. The computer transmits a vehicle information such as engine diagnosis result to the radio communication unit through a communication line. The radio communication unit communicates the received vehicle information to an external site of communication in response to a request of the information form the external site of communication irrespective of the supply of the electric power to the computer. Preferably, the supply of the electric power from the battery to the computer is maintained for a predetermined period after the vehicle operation.

Abstract: In a vehicle diagnosis information communication system, electric power is supplied from a battery to a vehicle control computer mounted on the vehicle during a period of vehicle operation, while the electric power is supplied to a radio communication unit mounted on the vehicle irrespective of the vehicle operation. The computer transmits a vehicle information such as engine diagnosis result to the radio communication unit through a communication line. The radio communication unit communicates the received vehicle information to an external site of communication in response to a request of the information form the external site of communication irrespective of the supply of the electric power to the computer. Preferably, the supply of the electric power from the battery to the computer is maintained for a predetermined period after the vehicle operation.

Abstract: A vehicle control system reduces the number of times learned value data is written into an electrically rewritable non-volatile ROM (EEPROM),. Learned value data (attained through learning control operation of a vehicle) is saved into the EEPROM, and then on battery disconnection, it can be transferred from the EEPROM back to an ordinary RAM instead of being lost. Each time engine rotating speed NE reaches a predetermined value (e.g., 500 rpm) after the ignition switch is turned on, a counter is incremented. When the counter reaches a predetermined count (e.g., the learned value data as of that time is written into the EEPROM for safe keeping and the counter is reset. Consequently, learned value data is written into the EEPROM in a manner which requires the vehicle to actually run a number of times, thereby making it possible to safely reduce the number of times the learned value data is written into the EEPROM for safe keeping.

Abstract: In a communication system which ensures that a slave device can successively transmit a plurality of answer messages without causing collision with another message on a communication line, in response to a request message from a diagnosis tester, control devices transmit their answer messages in the order of their priorities, with a communication blank duration provided between answer messages. If any one of the control devices has first and second answer message to be transmitted successively, the control device transmits the second answer message a communication blank duration after completing transmission of the first answer message. The control device can thereby transmit the first and second answer messages before a control device of a lower priority starts to transmit its answer message. Message collision on the communication line is thus avoided.

Abstract: When a framing error occurs in a slave unit, the cause of error is analyzed, and an interruption is inhibited or enabled depending on the cause of error thus, optimal data communication can be performed. When an interrupt request is issued, whether or not the interruption is caused by a framing error is determined. If the interruption is affirmatively caused by a framing error, whether or not framing errors occur two or more times is determined. An interruption is not inhibited (i.e., enabled) for a negative determination.

Abstract: A control unit of a self-diagnosis apparatus for a vehicle includes a CPU and a non-volatile RAM, wherein the CPU has a function of detecting abnormalities occurring in vehicle-mounted devices and of inputting diagnostic data for the vehicle-mounted devices necessary for the analysis of detected abnormalities. In the case of an abnormality occurring in a particular vehicle-mounted device during two consecutive trips, the abnormality is judged to be a final abnormality, whereas an abnormality of the particular vehicle-mounted device detected during the first trip was judged to be only a temporary abnormality. Moreover, updating of the diagnostic data is inhibited for a second abnormality as is subsequent final storage of the diagnostic data for an abnormality occurring in the second vehicle-mounted devices.

Abstract: A self-diagnosis apparatus for vehicle capable of storing sufficient data useful for abnormality diagnosis includes a control unit having a CPU and RAM which can hold its stored contents even at the time of cut-off of an ignition key. The CPU receives diagnosis data necessary for analysis of the abnormality of an equipment at each predetermined period and judges whether or not the value of the diagnosis data exists in a predetermined region, in order to count up a counter of a predetermined storage region beforehand provided in the RAM corresponding to the judged region. The counting-up is stopped when the abnormality of an equipment is detected. In contrast with a method in which the value of diagnosis data is stored into the RAM as it is, the range of change of a lot of diagnosis data until the generation of abnormality can be stored with a small memory size.

Abstract: Data communication equipment which includes a plurality of CPUs and transfers data between these CPUs, and which simplifies the circuit construction necessary for the data transfer. A monitor device transfers a request data containing a CPU number (corresponding to CPUN 1) storing a desired trouble data and an address (corresponding to ADR 1) storing the trouble data, to a second CPU. The requested data is sequentially transferred to the first CPU and the third CPU, and the CPU designated by CPUN 1 transfers the trouble data (DATAO 1, DATAO 3) and the address (ADRO 1, ADRO 3) storing the trouble data, to the monitor device. For this reason, each CPU need not be connected individually to the monitor device 43.

Abstract: The present invention provides an abnormality detecting device for a vehicle communication system comprising controllers and a diagnosis unit. The controllers store data to be transmitted by means of a communication IC to the diagnosis unit. When data is transmitted to a bus at a first timing, a communication abnormality, if any, around the communication IC is detected in response to the status of data stored in the communication IC at a second timing by a CPU. The CPU determines as an abnormality a case where, after transmission of data from the communication IC to the bus, the data is kept stored in the communication IC. The CPU determines as an abnormality a case where, after transmission of part of data to the communication IC, no data is stored in the communication IC.

Abstract: A control unit 1 has a CPU 101 and a backup RAM 102. The CPU 101 detects diagnostic data necessary for analyzing malfunctions of instruments installed in a motor vehicle, and updates and stores the data in sequence in the backup RAM 102 so that when malfunctions are detected, the CPU 101 inhibits updating and storing of the diagnostic data. Further, the control unit stores the malfunction detection history before the updating and storing inhibiting operation immediately after the malfunction has been detected. Therefore, even if an ignition switch is turned off before the updating and storing inhibiting operation, the malfunction detection history is referenced after the ignition switch is turned on again; when there is a detection history, the updating of the diagnostic data is inhibited so that the diagnostic data is prevented from being reset by mistake when the power supply is turned on again.

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.

Abstract: A self-diagnosing apparatus for a vehicles capable of reliably storing diagnostic data on high priority malfunctions. A control unit comprises a CPU and a RAM for storing stores contents even when an ignition key is turned off. The self-diagnosing apparatus detects a plurality of malfunctions. The plurality of malfunctions are classified into high priority malfunctions and low priority malfunctions. The RAM has a plurality of storage areas including a first frame and a second frame, the first frame being made to correspond to high priority malfunctions and the second frame to low priority malfunctions. The CPU inputs diagnostic data from each section of the motor vehicle necessary for analyzing instrument malfunctions and updates the stored contents of each area of the first and second frames.

Abstract: A self-diagnostic apparatus of vehicles which allows frozen diagnostic data to reflect correctly and efficiently a vehicle state upon the detection of an abnormality. A control unit has a CPU and a RAM which holds stored data even when the ignition key is turned off. The CPU detects an abnormality of individual on-board devices and when an abnormality of a device is detected, it stops updating diagnostic data and maintains data immediately prior to the detection of the abnormality. When updating of diagnosis data is not stopped, the contents of the RAM is updated at a predetermined updating period of time with diagnostic by data necessary for analyzing the device abnormality. The updating period becomes shorter as the rate of change of the diagnostic data grows larger. Through this, an adequate amount of diagnostic data near a time point at which the device abnormality occurs can be reliably and efficiently stored for later retrieval.