Checking variable intake manifold flap change-over valve N239 — AUDI

🧭 Before you start

With a helper watching, idle the engine and switch off; the flap should close and reopen after about 3 seconds. Check the mechanism, vacuum unit and vacuum lines, then measure N239 resistance at 25 to 45 Ω. Measure supply voltage at the connector at idle and at switch-off. If the valve and supply are correct, connect the test box and check the wiring for open circuit and shorts before renewing J248.

Fits: platform codes 70A, 70B, 70C, 70E, 70H, 70J, 70K, 70L, 70M, 7DA, 7DB, 7DC, 7DE, 7DH, 7DJ, 7DK, 7DL, 7DM

Don't miss

• Get a second person to watch the flap lever at switch-off.
• Check the linkage by hand and vacuum lines for correct routing before electrical tests.
• N239 resistance must be 25 to 45 Ω.
• At least 4.5 V at idle; at switch-off it rises, then drops to 0.0 V.
• Line resistance between test box and connector must not exceed 1.5 Ω.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

📐 20 workshop diagrams for ACV

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Start engine and run at idling speed.
2. Switch off ignition.
3. Observe positioning lever on intake manifold flap (2nd person required).
4. The intake manifold flap must, after switching off ignition, close and after approx. 3 seconds open again.
5. Check intake manifold flap change-over mechanics for freedom of movement. To do this, operate rods by hand.

6. Check function of vacuum unit with hand vacuum pumpV.A.G 1390.
7. Check that vacuum lines are connected correctly.
8. Check variable intake manifold flap change-over valve N239.
9. Pull connector off variable intake manifold flap change-over valve N239.
10. Measure resistance between contacts of variable intake manifold change-over valve N239: Specification: 25...45 Ω.
11. Renew variable intake manifold flap change-over valve N239.
12. Set multimeter to measure voltage and connect to contacts 1 and 2 of disconnected connector from variable intake manifold flap change-over valve N239.
13. Start engine and run at idling speed. Specification: at least 4.5 V
14. Switch off ignition. The voltage value must increase to battery voltage and fall to 0.0 V after approx. 3 seconds.
15. Connect test boxV.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 boxV.A.G 1598/31Electrical system; Rep. Gr. 94; Lights, bulbs, switches - exterior.]
16. Check lines/wiring between test boxV.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
17. Also check wiring for short to one another, short to vehicle earth and short to battery positive. Specification: ∞ Ω
18. Renew diesel direct injection system control unit J248

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