Checking intake manifold change-over valve: Audi 1.6 (AHL, ALZ, ANA, ARM)
Step-by-step checking intake manifold change-over valve for the Audi 1.6: factory workshop text. What to remove, in what order, and what to check after.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 14 workshop diagrams for AHL
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
ALZ
Electrical test of intake manifold change-over valve
-N156
Fitting location => Page
24-150
.
Unplug connector on intake manifold change-over valve.
Measure resistance at intake manifold change-over valve.
Specification: 25 ... 35 ohm
If the value is not as specified, fit a new valve.
Testing power supply to intake manifold change-over valve
-N156
Unplug connector for intake manifold change-over valve.
Connect diode test lamp V.A.G 1527 between engine earth and contact 1 (positive) on connector using cables from adapter set V.A.G 1594.
Operate starter briefly (the engine can be allowed to start).
Specification: the diode test lamp should light up.
If the diode test lamp does not light up, carry out the following tests:
Test fuse for -N156.
Test for open circuit in wiring between fuse and contact 1 on connector for intake manifold change-over valve using current flow diagram.
=> Current flow diagrams, Electrical fault finding and Fitting locations binder
Specification: max. 1 Ohm
Test fuel pump relay and activation => Page
24-56
.
Testing activation of intake manifold change-over valve
Connect diode test lamp V.A.G 1527 between contacts 1 (positive) and 2 (activation signal from engine control unit) on connector for intake manifold change-over valve using cables from adapter set V.A.G 1594.
Start final control diagnosis =>Page
01-53
. The diode test lamp should flash when the intake manifold change-over valve is being activated.
If the diode test lamp does not flash or lights up continuously, connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself => Page
24-26
.
If the diode test lamp lights up continuously, test for short to earth in wiring between contact 2 on connector for intake manifold change-over valve and socket 117 on test box.
If the diode test lamp does not flash, test for open circuit or short to positive in wiring between contact 2 on connector for intake manifold change-over valve and socket 117 on test box.
Specification: max. 1 Ohm
If necessary, rectify open circuit or short to earth.
If there is no open circuit and no short circuit, fit a new engine control unit
=> Page
24-30
.
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.
Ask about my car →Other AUDI procedures
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- Testing fuel gauge sender
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- Removing engine – Audi A8 D3 · 41 torque figures
- Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
- Installing engine – Audi A8 D4 · 36 torque figures
- Removing and installing camshaft timing chain · 29 torque figures
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.