| Testing databus (CAN bus) |
| Two data BUS circuits with a different priority are integrated in the electrical system of the vehicle: |
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| Convenience CAN data bus |
| The control units are connected via two twisted data BUS cables (CAN_High and CAN_Low) and exchange information (messages). Both the engine control unit and the other control units detect missing information on the data BUS as faults. |
| Special tools and workshop equipment required |
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| Hand multimeter (e.g. -V.A.G 1526 A-) |
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| Adapter cable set (e.g. -V.A.G 1594 A-) |
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| Test box -V.A.G 1598/22- or -V.A.G 1598/31- |
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| A data BUS fault was detected by the engine control unit. |
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| Coding of all control units o.k. |
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| Unlock connector at engine control unit and unplug. |
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| Connect test box-V.A.G 1598/22- or -V.A.G 1598/31 - to engine control unit → Chapter. The control unit wiring loom is not connected. |
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| Test the central terminating resistor in the engine control unit. |
| Test box -V.A.G 1598/22 - |
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| Measure resistance between test box sockets 20 + 21. |
| Test box -V.A.G 1598/31 - |
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| Measure resistance between test box sockets 31 + 32. |
| If the resistance is not within the specified range: |
| If the resistance is within the nominal value range: |
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