| The auxiliary heater control unit -J364- receives information from electrical and electronic components (information transmitters) which is then processed on the basis of the specifications. |
| The output signals of the auxiliary heater control unit -J364- then control the electrical components (control elements). |
| The auxiliary heater control unit -J364- is provided with a fault memory to permit rapid determination of the cause of the trouble in the event of component failure or an open circuit in the wiring. |
| Faults occurring in monitored sensors and components are stored in the fault memory together with an indication of the type of fault. |
| The first step in the fault-finding process is always to start self-diagnosis and interrogate the faults stored. This can be implemented by way of the following: |
| Special tools and workshop equipment required |
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| Vehicle diagnostic, testing and information system -VAS 5051A- |
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| Vehicle diagnostic and service information system -VAS 5052- |
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| K-wire adapter -VAS 6017B- (or K-wire adapter -VAS 6017A-) |
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| Fault reader -V.A.G 1551- |
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| Vehicle system tester -V.A.G 1552- |
| The fault information displayed is used in conjunction with a fault table (containing information on possible causes of trouble) to perform pin-pointed repair measures. |
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| If a fault situation exists for longer than a certain period, the fault is stored as being static. If the fault situation is then no longer detected for a pre-determined period, the fault is re-classified as being sporadic. This process is constantly repeated. Sporadic faults are additionally identified as such by /SP on the display. |
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| A sporadic fault is erased automatically if it no longer occurs for a pre-determined period. |
| The self-diagnosis options can be utilised for example by employing the vehicle diagnostic, testing and information system -VAS 5051A-, the vehicle diagnostic and service information system -VAS 5052-, the fault reader -V.A.G 1551- or the vehicle system tester -V.A.G 1552- in mode “1”“Rapid data transfer”. |
| Self-diagnosis is not restricted to storage, interrogation, erasing and final control diagnosis. It also has basic setting, control unit identification, adaption and encoding functions. |
| Mode -2- (flash code output) is not available for the auxiliary heater. Modes -3- (self-test) and -4- (workshop code) only apply to the fault reader -V.A.G 1551- and the vehicle system tester -V.A.G 1552- and are described in the relevant operating manuals. |
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