Diagnostic System for Motor Vehicles

Abstract

An electronic control unit for a motor vehicle diagnostic system includes a diagnostic module for identifying and storing faults; a decision module, by way of which specific fault reactions are assigned to each identifiable fault and specific customer complaint states are assigned to the fault reactions; and a generation module for generating a defined fault status. For each fault which is set in the fault memory and can be transmitted to a diagnostic tester external to the vehicle by way of a fault log, the fault status can be generated such that all customer complaint states assigned to the fault can be identified from the fault log in the diagnostic tester. The decision module is also provided to a suitable diagnostic tester having a transmission interface to the at least one electronic control unit.

Claims

1-4. (canceled)

5. An electronic control unit for a motor vehicle, the electronic control unit comprising: a diagnostic module for identifying and storing faults, a decision module which is used to assign fault reactions to each identifiable fault and to assign customer complaint states to the fault reactions, and a generation module for generating a defined fault status which is generatable for each fault, which has been set in a fault memory and is transmittable to a diagnostic tester outside the vehicle using a fault log, such that all customer complaint states assigned to the fault are identifiable from the fault log in the diagnostic tester.

6. A diagnostic tester comprising: a transmission interface to the electronic control unit according to claim 5, and an evaluation unit which is configured to identify assigned customer complaint states from a defined fault status of a fault that has been transmitted by the electronic control unit.

7. A diagnostic system comprising the electronic control unit according to claim 5, wherein a number of customer complaint states is less than a number of fault reactions.

8. The diagnostic system according to claim 7, further comprising: a transmission interface to the electronic control unit, and an evaluation unit which is configured to identify assigned customer complaint states from a defined fault status of a fault that has been transmitted by the electronic control unit.

9. A fault memory status for the electronic control unit according to claim 5, wherein: the fault memory status is generated as binary code with a predefined number of bits, and each bit position is assigned to a possible customer perception state.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 shows the most important components according to an embodiment of the invention in an electronic control unit.

[0021] FIG. 2 shows the most important components according to an embodiment of the invention in a tester.

[0022] FIG. 3 shows an example of a decision module according to an embodiment of the invention on the basis of a first and a second table structure.

DETAILED DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows the most important components according to the invention in an electronic control unit 1 having a diagnostic module 2 for identifying and storing faults FS_y and having a decision module EM.

[0024] As a result of the appropriate configuration of the control unit 1, in particular with regard to the diagnostic module 2 and the decision module EM, fault reactions (FR_x; with index x=1, 2, 4,...) determined by development are assigned, according to an embodiment of the invention, to defined faults (FS_y; with index y=1, 2, 4,...), on the one hand, and to the known customer complaints in the form of defined customer perception states (FZD_i; with index i=1, 2, 4,...), on the other hand. These assignments by way of the decision module EM are made available both in the control unit 1 and in the tester 4 (FIG. 2). The control unit 1 may transmit these assignments for storage in the tester 4 each time the tester is connected.

[0025] In the control unit 1, a check is preferably carried out in order to determine whether a specific fault FS_y triggers one or more of the previously determined fault reactions FR_x which in turn result in a defined customer perception state FZD_i. If this is the case, the fault memory status “Status_EM” defined according to an embodiment of the invention is output to the tester 4 in the workshop.

[0026] This new fault memory status “Status_EM” is preferably a binary code with a predefined number of bits, wherein each bit position is assigned to a possible customer perception state (FZD_i).

[0027] FIG. 2 schematically illustrates a diagnostic tester 4 which can be connected to the control unit 1. The diagnostic tester 4 is in turn preferably configured in such a manner that it is aware of the bit assignment of the fault memory status “Status_EM” which identifies the customer perception state FZD_i using a bit (“1”) which has been set at a particular bit position.

[0028] FIG. 3 shows an example of a possible decision module EM, that is to say an overall table structure, which is used to assign specific fault reactions FR_x to faults FS_y (via the transverse locking matrix) and to assign specific customer complaint states FZD_i to the fault reactions FR_x. Block formation (“clustering”) for iteratively locating faults more quickly takes place by way of the customer complaint states FZD_i, the number of which is less than the number of fault reactions FR_x.

[0029] Development stipulates beforehand, for example, that the fault reaction FR_1 results in comparatively little torque limitation, FR_2 results in comparatively high torque limitation, FR_3 results in comparatively little speed limitation and FR_4 results in comparatively high speed limitation. These FR_y all correspond to the customer perception “My vehicle no longer accelerates correctly” or the customer perception state FZD_1.

[0030] FR_5 results in a forced engine start, for example, and FR_6 results in prevention of an engine stop. These FR_y correspond to the customer perception “The engine automatic start/stop system no longer functions” or the customer perception state FZD_2.

[0031] For example, FZD_2 is assigned to the bit position Bit1 and FZD_2 is assigned to the bit position Bit2 of the fault memory status “Status_EM”. Bit1 is therefore assigned to the customer perception state FZD_1 “My vehicle no longer accelerates correctly” and Bit2 is assigned to the customer perception state FZD_2 “The engine automatic start/stop system no longer functions”.

[0032] If, for example, a fault FS_y with the fault reaction FR_6 were to occur and be set in the fault memory of the control unit 1, the statement by the customer in the workshop would be: “The engine automatic start/stop system no longer functions”.

[0033] The workshop now reads the fault memory as standard using the tester 4 and can check according to an embodiment of the invention whether Bit2 has been set (“1”) in the fault memory status “Status_EM”. Since this is the case in the example, the processing of the fault rectification measure can be specifically started here by first of all dealing with all faults FS_y which have been set and result in the customer perception state FZD_2.

[0034] Therefore, starting from the more general customer perception, the transverse locking matrix QVM or the decision module EM can be used to work back to the details of the fault reactions FR_x and finally the cause of the fault.