Testing wiring connection between white diagnostic connector and gearbox control unit — AUDI

Note:

The test of the K-wire as described in this chapter must be carried out if any of the following displays appear on fault reader V.A.G 1551 when connected:

Rapid data transfer
Fault in communication build up
Indicated on display:

or

Rapid data transfer
HELP
K wire not switching to earth

or

Rapid data transfer
HELP
K wire not switching to positive

Testing K-wire

The white diagnostic connector is connected to the gearbox control unit via junction K in the relay plate with fuse carrier:

=> Current flow diagrams, Electrical fault finding and Fitting locations

With the ignition switched off, connect test box V.A.G 1598/A using adapter V.A.G 1598/5 to connector of gearbox control unit
=> Page
01-70
.
Test for open circuit and short to positive or earth in the following wiring connection:

White diagnostic connector / Contact · Junction · Test box V.A.G 1598 A / Socket
2 · K · 51

Notes:

All diagnostic wires of the various on-board systems are linked to junction K. A defective wire (short circuit to earth or positive) or a defective control unit can also cause one of the fault readings mentioned above.
If wires of different colours are connected to junction K, identify the wiring colours for each of the on-board systems

=> Current flow diagrams, Electrical fault finding and Fitting locations

If wires of the same colour are connected to junction K, identify the relevant diagnostic wire with test box V.A.G 1598 A (resistance measurement range).

In this case trace the fault as follows:

One-by-one detach the connections for the other on-board systems with self-diagnosis capability from junction K.
Each time after a connector for a specific vehicle system has been detached, turn on the ignition and re-enter address word"02" for gearbox electronics.

If the gearbox control unit identification now appears on the display:

After switching on the ignition, enter address word "00" for automatic test sequence to find out to which control unit the disconnected wire is linked to.
Test diagnostic wire of disconnected control unit or renew control unit as required.