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Volkswagen Workshop Service and Repair Manuals

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Checking signal from/to air conditioning system > < Checking speed signal

Golf Mk4

Checking gear change signal from automatic gearbox
Checking gear change signal from automatic gearbox
The engine control unit receives the gear change signal from the gearbox control unit via the data bus wire. The engine control unit briefly reduces the amount of fuel injected. This reduces the torque and the gear change jolt.
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- with diagnosis cable -V.A.G 1551/3-
t  Adapter -V.A.G 1598/22-
t  Hand multimeter -V.A.G 1526C- or multimeter -V.A.G 1715-
t  Adapter set -V.A.G 1594C-
t  Current flow diagram
Test procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select control unit for engine electronics with “address word 01”. Engine must be idling. (Connect fault reader and select engine electronics control unit → Chapter.)
  WARNING
Secure fault reader to rear seat and operate from this position.
   
Indicated on display:
–  Press keys 0 and 8 for function “Read measured value block” and confirm entry with Q key.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Press keys 0, 0 and 9 for “Display group number 9” and confirm entry with Q key.
–  Carry out road test and when doing this observe display (2nd person necessary).
–  Observe displayed figure in display zone 3 when changing into 2nd gear: Specification: less than 51 mg/stroke for short period
  Note
Because data transfer is slow, display of the specification may be delayed in some circumstances.
If the specification is not reached:
–  Press → button.
–  Press keys 0 and 6 for function “End data transfer” and confirm entry with Q key.
–  Switch off ignition.
  
Read measured value block           HELP
Input display group number XXX
–  Connect adapter -V.A.G 1598/22- to control unit wiring harness.
–  Check wiring connection from engine control unit to gearbox control unit for open/short circuit → Current flow diagrams, Electrical fault finding and Fitting locations
  N24-0709

Checking signal from/to air conditioning system > < Checking speed signal