Checking air recirculation valve for turbocharger N249: Audi TT Mk1 (AJQ, AMK, AMU, APP, …)

🧭 Before you start

Fits: Audi TT Mk1 (8N)

• Special tools named: VAS 5051/1

Don't miss

• Turbocharger air recirculation valve N249 is supplied with power via fuel pump relay J17.
• Connect adapter cable, 121-pinV.A.G 1598/31 (test box) to connectors of wiring harness; do not connect engine control unit. Connect earth clip of test box to earth (arrow)24.
• Secure all hose connections with the correct type of hose clips (same as original equipment) Parts catalogue.

🔧 Engine codes this applies to

📐 43 workshop diagrams for AJQ

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

📋 Procedure

1. Connect up vehicle diagnostic, testing and information system VAS 5051B with diagnosis lead VAS 5051/1, press Vehicle self-diagnosis key and select vehicle system "“01 - Engine electronics”". When doing this, the engine must be running at idling speed.
2. From list (1), select diagnosis function "“02 - Interrogate fault memory”".
3. Terminate function "“02 - Interrogate fault memory”" by touching ← key.
4. Press function "“06 - End output”" and switch off ignition.
5. Remove engine cover panel (1) and cover (2) in front of intake manifold (arrows).

6. Detach pipe for secondary air system from brackets on engine (arrows).
7. Remove bolts (2) and (3) and detach bracket for dipstick guide tube (4).
8. Unplug electrical connectors (1) for turbocharger air recirculation valve N249 and secondary air inlet valve N112 on underside of retainer.
9. Detach vacuum hose going to electrical change-over valves at intake manifold.
10. Disconnect both hoses from secondary air pump.
11. Disconnect hoses from turbocharger air recirculation valve N249(item 7); re-attach electrical connector. [Note: The illustration shows the retainer for electrical change-over valves from below and removed from the engine. Illustration shows version for vehicles with secondary air system. On vehicles without secondary air system, only the turbocharger air recirculation valve N249 is fitted to the retainer for electrical change-over valves. Disregard (items 1 ... 6).]
12. Connect test hose to the hose connection on the turbocharger air recirculation valve N249 marked with an (arrow).
13. Switch on ignition and select vehicle system "“01 - Engine electronics”".
14. From the menu (1) select the diagnostic function "“03 - Final control diagnosis”".
15. Press the → key repeatedly until the following display appears:
16. Press the ← key to exit from function "“03 - Final control diagnosis”".
17. Press function "“06 - End output”" and switch off ignition.
18. Renew air recirculation valve for turbocharger N249.
19. Unplug electrical connector at turbocharger air recirculation valve N249.
20. Connect hand-held multimeter V.A.G 1526C to measure resistance between contacts on turbocharger air recirculation valve N249.
21. Renew air recirculation valve for turbocharger N249. [Note: Turbocharger air recirculation valve N249 is supplied with power via fuel pump relay J17.]
22. Connect voltage tester V.A.G 1527B between contact (1) of connector for turbocharger air recirculation valve N249 and earth "“–”".
23. Operate the starter briefly.
24. Check for open circuit in wiring from contact (1) of connector for turbocharger air recirculation valve N249 via fuse to fuel pump relay J17.
25. Repair wiring connection if necessary.
26. Connect voltage tester V.A.G 1527B between contact (1) and (2) of connector for turbocharger air recirculation valve N249.
27. Switch on ignition and select vehicle system "“01 - Engine electronics”".
28. Repeat function "“03 - Final control diagnosis”".
29. Press the → key repeatedly until the following display appears:
30. Press the ← key to exit from function "“03 - Final control diagnosis”".
31. Press function "“06 - End output”".
32. Switch off ignition and detach diagnostic connector.
33. Connect adapter cable, 121-pin V.A.G 1598/31 (test box) to connectors of wiring harness; do not connect engine control unit. Connect earth clip of test box to earth (arrow)24.
34. ⚠ To prevent damage to electronic components, select appropriate measuring range before connecting measuring leads and observe test requirements. — Check for open circuit and short to positive or earth in the following wiring:
35. Repair wiring connection if necessary. [Note: Secure all hose connections with the correct type of hose clips (same as original equipment) Parts catalogue.]

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