Checking idling stabilization — VW

On vehicles 10.91▸the idling stabilization valve is checked via the self diagnosis.

Special tools, testers and auxiliary items

Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
Adapter set V.A.G 1594

Functional check

Switch on ignition.

Idling stabilization valve -1- (N71) must vibrate and buzz.

Valve vibrates and buzzes:

Check regulation.

Valve does not vibrate and buzz:

Switch off ignition.
Pull plug of valve -1- and connect hand multimeter V.A.G 1526 with aux. cables from V.A.G 1594 to check valve resistance.

Specification: 2...10 ω

If the specification is not attained:

Renew valve.

If the specification is attained:

Carry out electrical check, Test steps 8 or 25
=>Page
01-32
, if necessary renew control unit.

Checking regulation

Check conditions

Engine oil temperature min. 80 °C
Idling adjustment OK. => Page
24-27
.
Intake system free of leaks, checking => Page
24-69

Test sequence

Connect hand multimeter V.A.G 1526 with measuring cable V.A.G 1315A/2 and aux. cables from V.A.G 1594 to idling stabilization valve -1-.
Check control current and idling speed (775...825 rpm1)) .
Specification: approx. 500...600 mA
Vehicles ä 12.92
Specification: approx. 420±30 mA, possibly fluctuating

1)
Up-to-date specifications:

=> Exhaust emissions test binder

With throttle valve closed pull plug off coolant temperature sender (blue, 2-pin) -arrow-.
Specification: approx. 500...600 mA
Vehicles ä 12.92
Specification: approx. 420±30 mA constant

Note:

If the engine stalls, reconnect plug to coolant temperature sender before restarting. Otherwise the control unit will introduce an emergency running programme and a correct check/adjustment is not possible.

If the specifications are not obtained:

Renew Digifant control unit (J169).

Note:

The control current for the idling stabilization is dependent upon the engine load at idling. The following loads can cause the control current to fluctuate between 400 and 1000 mA:

Engine cold.
Air conditioner switched on.
Electrical consumers switched on.
Power assisted steering: wheels not in straight-ahead position.
Idle speed adjusting screw, fully screwed in (vehicles▸12.92).
Ignition timing not correct.