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| Use the relevant current flow diagrams to determine which control units have been connected to the data bus drive (CAN bus, Controller Area Network) |
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| Check tight fit of the plug connections of all connected control units. |
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| Connect vehicle system tester -V.A.G 1552- and select function 00 “Automatic test sequence”. |
| Before testing the communication cable check whether there are no functional faults in the connected control units. |
| Special tools and workshop equipment required |
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| Handheld multimeter (e.g. -V.A.G 1526-) |
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| Measuring tool set (e.g. -V.A.G 1594-) |
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| Test box -V.A.G 1598/31- |
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| Self-diagnosis has determined a fault in the data bus. |
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| Release connector from engine control unit and unplug. |
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| Connect test box -V.A.G 1598/31- to the engine control unit. Do not connect cable to the engine control unit → Chapter. |
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| Check mean terminating resistance in the engine control unit and measure the resistance between the test box-bushes 6 and 7. |
| Specified value: 60...72 Ω |
| If the measured value does not correspond to the specified value: |
| If the measured value corresponds to the specified value: |
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