Checking variable intake manifold flap change-over valve N239 — VW
Checking variable intake manifold flap change-over valve N239 on VW: factory workshop procedure for engines ACV, AGD, AHY, AJT.
Workshop procedure for VW — the factory write-up, straight from real workshop data.
📐 20 workshop diagrams for ACV
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
Checking
variable intake manifold flap change-over valve
N239
Special tools and workshop equipment required
Hand vacuum pump
V.A.G 1390
Test box
V.A.G 1598/31
Hand-held multimeter
V.A.G 1526C
Auxiliary measuring set
V.A.G 1594C
Current flow diagram
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 unit with
hand vacuum pump
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 contacts of
variable intake manifold change-over valve
N239
: Specification: 25...45 Ω.
If the specification is not attained:
Renew
variable intake manifold flap change-over valve
N239
.
If specification is attained:
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: at least 4.5 V
Switch off ignition. The voltage value must increase to battery voltage and fall to 0.0 V after approx. 3 seconds.
If the voltage values do not change as described:
Connect
test box
V.A.G 1598/18
to control unit wiring harness.
Note
If necessary, left headlight may have to be released and placed to side to connect
test box
V.A.G 1598/31
Electrical system; Rep. Gr. 94; Lights, bulbs, switches - exterior
.
Check lines/wiring between
test box
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
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.