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Intake manifold change-over function, checking Audi A6 C5 facelift

Multiport Fuel Injection (Mfi) - 3.0L V6 Avk 8 illustrations ~417 words

Intake manifold change-over function, checking

This check should only be carried out if the engine is losing power.

Scheme 467

Scheme 467: Intake manifold change-over function, checking
Scheme 467: Intake manifold change-over function, checking

Scheme 468

Scheme 468
Scheme 468
  1. Remove front engine cover (arrows).
  2. Start engine and increase engine speed to over 4200 RPM. Operating rods of actuator for intake manifold (arrow) must move

If the change-over is not taking place, perform the following checks

  1. Check Intake manifold change-over valve -N156 -. Perform output DTM. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(ref-216419-S06564205212006012100000) . If necessary, check valve and activatio «INTAKE MANIFOLD CHANGE-OVER VALVE -N156-, CHECKING»(ref-216420-S42534240082006012100000) or «CHECKING ACTIVATION»(ref-216420-S19587736912006012100000) .
  2. Check vacuum system for leaks. See «VACUUM SYSTEM, CHECKING FOR LEAKS»(ref-216420-S07322805522006012100000) .
  3. Check that vacuum hoses are properly connected and free of leaks and obstructions.
  4. Check that change -over mechanism operates freely (move push rod by hand).

Scheme 469

Scheme 469: Special tools and equipment
Scheme 469: Special tools and equipment
  1. VAG1348/3-2
  2. VAG1348/3A
  3. VAG1390
  4. VAG1594 A

Scheme 470

Scheme 470: Test sequence
Scheme 470: Test sequence

Scheme 471

Scheme 471
Scheme 471

Scheme 472

Scheme 472
Scheme 472
  1. Run engine at idling speed for 2 or 3 minutes to build up vacuum pressure.
  2. Switch ignition off.
  3. Remove front engine cover (arrows).
  4. Disconnect connector to Intake manifold changeover valve -N156 - -1-. NOTE: Ignore item -2-.
  5. Connect one terminal on solenoid valve to engine Ground using test leads and alligator clamp from VAG1594 A.
  6. Connect second terminal on intake manifold change-over valve -N156- to positive using remote control VAG1348/3A, adapter lead VAG1348/3-2 and auxiliary cable.
  7. Operate remote control VAG1348/3A approx. 2 to 3 minutes; throughout this period, vacuum module should remain energized.

If the vacuum module retardations to its original "rest" position, perform the following test

Scheme 473

Scheme 473
Scheme 473
  1. Disconnect vacuum hoses from vacuum module for intake manifold change-over system.
  2. Connect hand vacuum pump VAG1390 to vacuum module.
  3. Operate hand pump and check whether change-over function is working.
  4. Check vacuum module for leaks. (Vacuum module should not return to rest position until hand pump is vented to atmosphere.)
  5. Replace vacuum module, if necessary.
  6. If vacuum module is not energized, check intake manifold change-over valve -N156- as follows for blockage
  7. Connect one terminal of intake manifold change -over valve -N156- to engine Ground using test leads and alligator clamp from VAG1594 A.
  8. Connect second terminal on intake manifold change -over valve -N156- to positive using remote control VAG1348/3A, adapter lead VAG1348/3-2 and auxiliary cable.
  9. Operate remote control VAG1348/3A.
  10. Check valve for obstructions (disconnect vacuum hoses and blow through).
  11. Replace intake manifold change -over valve, if necessary.
  12. If no DTCs have been found in any test, check vacuum system for leaks.

Scheme 474

Scheme 474: Special tools and equipment required
Scheme 474: Special tools and equipment required
  1. VAG1526 A
  2. VAG1527 B
  3. VAG1594 A
  4. VAG1598/31
  5. VAS5051 with VAS5051/1