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Skoda Workshop Service and Repair Manuals

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Ignition system, glow plug system > < Checking the data BUS

Fabia Mk1

Testing cruise control system
Testing cruise control system
Apart from the control switch on the steering column switch the cruise control system (CCS) has no other components. All functions are performed by the diesel direct injection system control unit - J248-. The data transfer from the control switch to the diesel direct injection system control unit - J248- occurs with a data BUS via the vehicle voltage control unit -J519-.
Special tools and workshop equipment required
t  Vehicle system tester -V.A.G 1552-
t  Diagnostic cable -V.A.G 1551/3-
t  Hand multimeter (e.g. -V.A.G 1526 A-)
t  Adapter cable set (e.g. -V.A.G 1594 A-)
t  Test box -V.A.G 1598/31-
Test conditions
l  Fuse 28 O.K.
l  Cruise control not activated.
–  Activate the cruise control → Chapter
Check for proper operation
–  Connect vehicle system tester - V.A.G 1552-. Leave the engine on and select the engine control unit with “Address word” 01 → Chapter.
–  Select function 08 “read measured value block” and display group number 006.
   
–  Readout on display:
–  Observe readout in display field 4.
   Specified value:
   0 = CCS disconnected
   1 = CCS connected
–  Observe readout in display field 3.
  
Reading measured value block         6   ->
0 km/h       000       000000         0
–  Operate the CCS switch according to the following table.
  N23-0199
Test conditionsDisplay field 3 
Switch B engaged on “OFF”000000 
Switch B on “OFF” before the activation point000001
Switch B on “ON”000011
Switch B on “RES”001011
Switch A pressed000111
Brake pedal actuated010011
Clutch pedal actuated100011

–  If the display does not occur as described:
–  Select function 06 “End output” and confirm entry with Q.
–  Switch off the ignition.
–  Test the wires of the CCS switch to the vehicle voltage control unit -J519- according to the current flow diagram.
   
–  Test the wire from the CCS switch to fuse 28 for interruption or short-circuit.
–  Connect the test box -V.A.G 1598/31 - to the diesel direct injection system control unit -J248-. The control unit wiring loom is not connected → Chapter.
–  Check the following wiring for open circuit or short circuit to earth or positive:
  S01-0094
10-pin CCS plug contactTest box -V.A.G 1598/31-, bush
414
714

If the wires are not found to be faulty:
–  Perform self-diagnosis of the vehicle voltage control unit -J519- → Electrical System; Rep. Gr.90
–  Checking the data BUS → Chapter
   

Ignition system, glow plug system > < Checking the data BUS