Skoda OCTAVIA MK1 Service Manual page 253

Test the wiring of contact 7 of the engine control unit connector to the automatic gearbox
–
control unit for interruption or short-circuit
For vehicles 08.97 ►
Test the wiring of contact 8 of the engine control unit connector to the automatic gearbox
–
control unit for interruption or short-circuit
Testing the speed signal
Note
The speed signal is generated by the vehicle speed sender -G68- (at gearbox) and
t
processed in the dash panel insert.
The processed signal passes to contact 20 of the engine control unit and is used for idling
t
speed stabilisation and for damping load change jolts during gearshifts.
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-
Connect vehicle system tester -V.A.G 1552- and select address word 01 "Engine
–
electronics". Ignition switched on.
– Enter function 08 "read measured value block" and select display group 002.
The following appears in the display:
Determine by means of a test drive whether the driving speed
–
is displayed in display field 3.
If the vehicle speed is not displayed, raise vehicle preferably
–
with the lift platform until the front left wheel is free.
Connect the test box -V.A.G 1598/22 - to the wiring loom of the
–
engine control unit
Connect the voltage tester between bush 3 (positive) and bush
–
20 (speed signal).
– Switch on ignition and turn the left front wheel by hand.
– The voltage tester must flash (very short flashing signal).
Note
The right front wheel must not turn along, if necessary hold.
→ Chapter.
→ Current flow diagrams and Fitting
→ Current flow diagrams and Fitting
253
locations.
locations.
Reading measured value
block 2
->
850/rpm 120 mg/s
0 km/s 0100