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Checking intake manifold flap motor V157 > < Checking intake manifold flap change-over

Golf Mk4

Checking function
Checking function
–  Start engine and run at idling speed.
–  Switch off ignition.
–  Observe positioning lever on intake manifold flap (2nd person required).
–  The intake manifold flap must, after switching off ignition, close and after approx. 3 seconds open again.
If change-over does not occur, the following checks must be carried out.
–  Check intake manifold flap change-over mechanics for freedom of movement. To do this, operate rods by hand.
–  Check function of vacuum actuator with hand vacuum pump with accessories -V.A.G 1390/-.
–  Check that vacuum lines are connected correctly.
If no fault is found in the mechanical components:
–  Check variable intake manifold flap change-over valve -N239-.
Test procedure
–  Pull connector off variable intake manifold flap change-over valve -N239-.
   
–  Measure resistance between change-over valve contacts.
Specification: 25…45 Ω
If the specification is not achieved:
–  Renew variable intake manifold flap change-over valve -N239-.
If the specification is attained:
  N23-0202
–  Set multimeter to measure voltage and connect to contacts 1 and 2 of disconnected connector from variable intake manifold flap change-over valve -N239-.
–  Start engine and run at idling speed.
Specification: approx. battery voltage
–  Switch off ignition.
–  The voltage value must fall to 0 V after approx. 3 seconds.
If the voltage values do not change as described:
  N24-1026
–  Connect adapter cable, 121-pin -V.A.G 1598/31- to control unit wiring harness.
  N24-0943
–  Check wiring between adapter cable, 121-pin -V.A.G 1598/31- and connector for open circuit referring to current flow diagram.
Contact 1 + sockets 1 and 2 Contact 2 + socket 81 Line resistance: max. 1.5 Ω
–  Also check wiring for short to one another, short to vehicle earth and short to battery positive.
Specification: ∞ Ω.
If no fault in lines is detected:
–  Renew diesel direct injection system control unit -J248- → Chapter.
  N24-1026

Checking intake manifold flap motor V157 > < Checking intake manifold flap change-over