| Checking matching resistor of data bus |
| The engine control unit communicates with other data bus-compatible control units. |
| The control units are connected via a twisted pair of data bus wires (“high” and “low”) and exchange information (messages). Information missing from the data bus will be recognised as a fault by both the engine control unit and other data bus control units. |
| The data bus requires a matching resistor to function fault free. This central matching resistor is located in the engine control unit. |
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| A data bus fault has been recognised by the self-diagnosis. |
| Special tools and workshop equipment required |
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| Test box -V.A.G 1598/22- |
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| Hand multimeter -V.A.G 1526- or multimeter -V.A.G 1715- |
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| Adapter set -V.A.G 1594- |
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| Unlock the engine control unit connector and pull it off. |
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| Connect test box -V.A.G 1598/22- to engine control unit. |
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| Check centralized matching resistor in engine control unit. |
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| To do this perform a resistance measurement between the test box Sockets 31 + 32 Specification: 60...72 Ω |
| If the resistance measurement is outside the specified range: |
| If the resistance value is within the specified range: |
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