Checking intake manifold flap change-over valve — VW

AGR ALH AQM ASV AYQ
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
Adapter set V.A.G 1594
Test box V.A.G 1598/22
Current flow diagram

Check conditions

The fuses must be OK.
Earth connection in plenum chamber OK.
The battery voltage must be at least 11.5 V.
All electrical consumers, e.g. lights and rear window heating must be switched off.

Test procedure (Engine codes AGP, AQM)

Test procedure (engine codes AGR, ALH, ASV)
=> Page
23-105
.

Pull 2-pin connector off intake manifold flap change-over valve (N239) -arrow-.

Measure resistance between change-over valve contacts.
Specification: 25.0 ... 45.0 ω

If the specification is not obtained:

Renew air intake connecting piece together with intake manifold flap change-over valve (N239)
=> Page
23-32
, Removing and installing air intake connecting piece.

Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page
01-12
, interrogating and erasing fault memory.

If the specification is obtained:

Set multimeter to measure voltage and connect to contacts 1 and 2 of disconnected connector from intake manifold flap change-over valve.
Start engine and run at idling speed.
Specification: at least 4.5 V
Switch off ignition. Value for voltage must drop to
0.0 V after about 3 seconds.

If the voltage values do not change as described:

Connect test box V.A.G 1598/22 to control unit wiring harness.

Check wiring between test box and connector for open circuit using current flow diagram.
Contact 1+socket 2
Contact 1+socket 28
Contact 2+socket 15
Wire resistance: max. 1.5 ω
Additionally check wires for short to one another, to vehicle earth and to battery positive.
Specification: ∞ω

If no fault is detected in the wiring:

Replace engine control unit
=> Page
23-134
.

Test procedure (engine codes AGR, ALH, ASV)

Pull 2-pin connector off intake manifold flap change-over valve (N239) -arrow-.

Measure resistance between change-over valve contacts.
Specification: 25.0 ... 45.0 ω

If the specification is not obtained:

Renew intake manifold flap change-over valve (N239)=> Page
23-28
, item
12
.
Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page
01-12
, interrogating and erasing fault memory.

If the specification is obtained:

Set multimeter to measure voltage and connect to contacts 1 and 2 of disconnected connector from intake manifold flap change-over valve.
Start engine and run at idling speed.
Specification: at least 4.5 V
Switch off ignition. Voltage must rise to battery voltage and
fall to 0.0 V after about 3 seconds.

If the voltage values do not change as described:

Connect test box V.A.G 1598/22 to control unit wiring harness.

Check wiring between test box and 2-pin connector for open circuit using current flow diagram.
Contact 1+socket 2
Contact 1+socket 28
Contact 2+socket 3
Wire resistance: max. 1.5 ω
Additionally check wires for short to one another, to vehicle earth and to battery positive.
Specification: ∞ω

If no fault is detected in the wiring:

Replace engine control unit
=> Page
23-134
.