Micro-computer system for control and diagnosis of motor vehicle functions

In a motor vehicle, the combination of

• apparatus forming part of the motor vehicle for electronically controlling functional elements of the vehicle and their operating functions including at least one of:
• ignition firing;
• fuel injection,
• wherein the apparatus includes
• an on-board microcomputer system (62) comprising a microprocessor unit (10), at least one fixed value memory unit (12-ROM, PROM, EPROM) storing operating and function data of the vehicle, a working memory unit (11-RAM), an input/output unit (13), a data bus (14) and an address bus (15), said buses interconnecting said units;
• at least one signal source (U, T, L, 30-39) coupled to a functional element of the motor vehicle and a signal processing circuit (29) connected to the respective signal source and providing one or more vehicle function parameter-dependent signals to the input/output unit (13);
• and at least one output element (47-58) connected to and controlled by said input/output unit, coupled to a functional element of the motor vehicle and controlling an operating function of the vehicle;
• with
• a monitoring and supervisory apparatus connectable to receive at least one vehicle function parameter-depending signal derived from at least one of said signal sources within said apparatus forming part of the motor vehicle, including
• a diagnostic equipment unit (66) connected to the input/output unit (13) and having a comparison diagnostic unit (68);
• means (69, 70) storing data representative of a diagnostic program including data representative of predetermined operating functions and diagnosis test command data;
• connection means (63, 64, 65, 64') connecting said diagnostic equipment unit to receive one or more vehicle function parameter-dependent signals;
• said connection means further (a) selectively connecting the diagnostic program into said microcomputer system (62) for processing in accordance with the diagnosis test command data and providing respective vehicle function parameter-dependent signals to the input/output unit (13) to affect a respective functional element of the motor vehicle, said connection means establishing communication with the respective functional element to permit supervision of the response of the respective functional element in accordance with the processed diagnosis test command data whereby the operation of the microcomputer system (62) as well as at least one signal source forming part of the motor vehicle and the respective functional element forming part of the motor vehicle can be checked and possible malfunction diagnosed;
• and (b) selectively providing connection of said input/output unit (13) of the microcomputer system (62) to the diagnostic equipment unit (66) and connection of at least one output element to the diagnostic equipment unit (66) to permit control of the respective output element from the stored data representative of said functions upon failure or malfunction of or in said microcomputer system (62) or in one of said signal sources.