Checking idling stabilisation valve -N71 — AUDI

Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1527 B
V.A.G 1594 A
V.A.G 1598 A
V.A.G 1598/3
VAS 5051 with VAS 5051/1 and VAS 5051/2

or

V.A.G 1551 with V.A.G 1551/1

Fitting location => Fitting locations overview, Page
25-5

Checking baffle plate

Switch ignition off.
Pull connector off idling stabilisation valve.

Connect multimeter to injector to measure resistance.
Specification: 4 ... 12 ω

Note:

Resistance is in the lower tolerance range at ambient temperature and in the upper tolerance range when the engine is warm.

If the specification is not obtained:

Renew idling stabilisation valve.

Mechanical checking

Remove idling stabilisation valve

Check piston slide -arrow- for scoring (visual inspection).

Note:

Never use a screwdriver or similar tool to move the piston slide when checking for freedom of movement.

Attach connector to removed idle stabilisation valve
Switch the ignition on.
Start final control diagnosis and actuate the idling speed stabilisation -N71 => Page
01-34
.
Check whether piston slide moves properly from stop to stop.

If scoring is found which impairs freedom of movement or if piston slide does not move freely (sticking, sluggish or not full range of travel):

Renew idling stabilisation valve.

If idling stabilisation valve does not react in final control diagnosis:

Checking power supply

Test requirements:

Fuse S75 in brown holder in electronics box in passenger footwell OK

Push back rubber grommet of plug for valve for idling speed stabilisation. However, connector remains plugged in.

Connect up multimeter as follows to measure voltage.

Connector / contact · Measure to
1 · Engine earth

Switch the ignition on.
Specification: approx. battery voltage

If the specification is not obtained:

Eliminate open circuit or short circuit using the current flow diagram.

If the specification is obtained:

Check actuation.

Checking actuation

Push back rubber grommet of plug for valve for idling speed stabilisation. However, connector remains plugged in.

Connect up voltage tester V.A.G 1527 B between contacts 1 and 2.
Start final control diagnosis and actuate the idling speed stabilisation -N71 => Page
01-34
.
The LED should flash.

If the specification is obtained:

Renew idling stabilisation valve.

If the specification is not obtained:

With the ignition switched off, use adapter V.A.G 1598/3 to connect test box V.A.G 1598 A to plug connection of engine control unit (control unit remains disconnected) => Page
25-10
.

Check for open circuit and short to positive or earth in the following wiring connection:

Connector / contact · Test box V.A.G 1598 A / socket
2 · 17

Rectify any open/short circuit as necessary.

=> "Current Flow Diagrams, Electrical Fault-finding and Fitting Locations" binder

If the wiring is OK and no activation is carried out:

Fit a new engine control unit => Page
25-13
.