| The control units capable of data bus are connected together via two data bus wires twisted together (CAN_High and CAN_Low) and exchange information (messages). Information not available in the data bus will be recognised as a fault by the engine control unit as well as other CAN data bus control units. |
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| A fault has been recognised by the CAN data bus self-diagnosis. |
| Special tools and workshop equipment required |
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| Adapter cable, 121-pin -V.A.G 1598/31- |
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| Hand multimeter -V.A.G 1526C- or multimeter -V.A.G 1715- |
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| Auxiliary measuring set -V.A.G 1594C- |
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| Release connector from engine control unit and pull off. |
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| Connect adapter cable, 121-pin -V.A.G 1598/31- to engine control unit. The control unit wiring harness is not connected by this action. |
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| Check terminating resistor in engine control unit. |
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| To do this, perform resistance measurement between sockets 6 + 7 of adapter cable, 121-pin -V.A.G 1598/31-: |
| If the resistance measurement is outside the specified range: |
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| Renew engine control unit. |
| If the resistance value is within the specified range: |
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