Skoda OCTAVIA MK1 Service Manual page 258

Test data bus
1 - Engine control unit
– Fitting location: in plenum chamber
2 - ABS control unit
Fitting location: at the hydraulic unit in
–
left of engine compartment
3 - Gearbox control unit
– Fitting location: in plenum chamber
4 - Databus driver
– Part of control unit
Operation
The engine control unit -1- communicates
with the ABS control unit -2- and the
gearbox control unit -3- via the data bus.
At least two control units with databus
capability are linked by two twisted
databus cables (CAN_High and CAN_Low)
and exchange information (messages).
Both the engine control unit and the other
CAN data bus control units detect missing
information on the data bus as faults.
In order for the databus to operate without
fault, the terminating resistance R must be
arranged in both control units before the
databus driver -4-. These terminating
resistances are located in the engine and
ABS control unit.
Special tools and workshop equipment
required
t Test box -V.A.G 1598/21-
t Test box -V.A.G 1598/22-
Handheld multimeter, e.g. -V.A.G 1526 A
t
-
t Measuring tool set, e.g. -V.A.G 1594 A-
t Current flow diagrams
Vehicles with automatic gearbox:
t Test box -V.A.G 1598/18-
Test conditions
258