Inspect The Vacuum System - Skoda OCTAVIA MK1 Service Manual

The vacuum box for the intake manifold
– switch-over must pull in, the shift linkage
must go back again to its initial position
-arrow-.
If the change-over does not occur, perform
the following tests:
Check variable intake manifold
– changeover valve -N156- (perform final
control diagnosis
check valve and actuation
Inspect vacuum lines for leaks
–
→ Chapter.
Inspect vacuum lines for proper
–
connection, leaktightness and continuity.
Check smooth operation of changeover
– mechanism. (Operate shift linkage by
hand.)

Inspect the vacuum system

Special tools and workshop equipment required
t Remote control, e.°g -V.A.G 1348/3 A- with adapter cable, e.g -V.A.G 1348/3-2-
t Hand vacuum pump, e.°g.° -V.A.G 1390 -
t Measuring tool set, e.g. -V.A.G 1594 A-
– Leave engine running at idling speed for 2 to 3 minutes (build up vacuum).
– Switch off ignition.
– Disconnect plug from valve for variable intake manifold changeover.
Connect one contact of the valve°with the connection line and alligator clip from -V.A.G 1594 A- to the
–
engine mass.
Lay a second contact of the valve with remote
control - V.A.G 1348/3A-, adapter cable
–
-V.A.G 1348/3-2- and connection line to
positive terminal.
Activate the remote control -V.A.G 1348/3A-
– for 2 to 3 minutes. During this period, the
vacuum unit must be connected.
If the vacuum unit does not return to its initial
position, check the vacuum unit as follows:
Remove the vacuum lines from the vacuum
–
unit for intake manifold changeover.
– Connect hand vacuum pump to vacuum unit.
Actuate the hand vacuum pump and observe
–
the switch over procedure.
Check vacuum unit for tightness. (The vacuum
unit must not return to its initial position as
–
long as it is not ventilated at the hand vacuum
pump).
→ Chapter, if necessary
→ Chapter).
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