Skoda OCTAVIA MK1 Service Manual page 254

If the voltage tester does not flash, test the wiring of contact 20
– at plug of engine control unit to dash panel insert for open
circuit and/or short circuit
locations.
Check signal for gearbox intervention during gearshifts
Note
By means of this signal from the automatic gearbox control unit, the ignition angle is
t briefly reduced (torque reduction) depending upon the speed and engine speed during
gearshifts of the automatic gearbox, in order to avoid the jerky gear change.
For vehicles ► 07.97, the signal is a rectangular signal, which arrives at contact 23 at the
t
engine control unit.
For vehicles 08.97 ►, the signal is a rectangular signal, which arrives via the data BUS at
t
contact 23 at the engine control unit.
Due to the very short signal, the request for ignition angle relief from -V.A.G 1552- is not
t
always detected.
Special tools and workshop equipment required
t Handheld multimeter, e.g. -V.A.G 1526 A -
t Vehicle system tester -V.A.G 1552 - with cable -V.A.G 1551/3-
t Measuring tool set -V.A.G 1594 A -
t Test box -V.A.G 1598/22-
Procedure
– Connect vehicle system tester -V.A.G 1552-
Conduct a test drive and select the function 08 "read measured value block" and display
–
group 001 → Chapter.
WARNING
The -V.A.G 1552- should be operated by a second person.
The following appears in the display:
Specified value: X 0 X X X X X X = without gearbox intervention
Specified value: X 1 X X X X X X = gearbox intervention
Value: X = no meaning
Note
→ Current flow diagrams and Fitting
254
→ Chapter.
Reading measured value
block 1
->
850/rpm
00000010
90°C 0.80 V