Intake system, checking for leaks using VAG 1687 Diagnostic Tool: Notes

Diagnostic trouble codes (DTCs) related to fuel trim, charge pressure or mass air flow (MAF) may be caused by:

• Leaking (worn/torn) intake hoses during charge conditions
• Incorrectly torqued or improperly placed clamps on intake hoses etc. causing leaks during charge conditions

Check the charge air pressure system using the VAG 1687 Charge air system tester.

Special tool VAG 1687 Charge air system tester preliminary set-up 

• Back off pressure regulator knob -2- of VAG 1687 fully to protect gauge when shop air supply is applied to assembly. See Fig 2.
• Close valve -3- before gauge.
• Close valve -4- after gauge.

  The shop air supply line will later be attached to the inle of VAG 1687.

  Fig 2: Special Tool VAG 1687 Charge Air System Tester

  Courtesy of AUDI OF AMERICA, INC.
• Remove female fitting from tester (arrow) and install an appropriate "male" air fitting that will connect to your shop air supply line.

Special tool VAG 1687/1 pressure adapter, installing (1.8L Turbo) 

• Separate intake hose from Mass Air Flow (MAF) sensor assembly.
• Insert VAG 1687/1 pressure adapter in intake hose -black arrow- using existing clamp (as shown).
• Remove crankcase ventilation tube from intake hose at white arrow-. See Fig 3.
  Fig 3: Inserting VAG 1687/1 Pressure Adapter In Intake Hose -Black Arrow- Using Existing Clamp (1.8L Turbo)

  Courtesy of AUDI OF AMERICA, INC.

Special tool VAG 1687/1 pressure adapter, installing (2.7L BiTurbo) 

• Remove upper air cleaner housing and hoses to intake manifold as necessary

  See AIR CLEANER HOUSING, CLEANING; AIR CLEANER ELEMENT, REPLACING .

• Insert VAG 1687/1 pressure adapter in intake hose -white arrow- using existing clamp (as shown).
• Disconnect engine crankcase ventilation hose from intake manifold -black arrow-. See Fig 4.
  Fig 4: Inserting VAG 1687/1 Pressure Adapter In Intake Hose -White Arrow- Using Existing Clamp (2.7L BiTurbo)

  Courtesy of AUDI OF AMERICA, INC.
• Plug intake manifold fitting (for crankcase ventilation hose) with appropriate hose and metal plug using clamps supplied with VAG 1687/1 special tool kit.
  NOTE:

  • To help find small leaks, BEFORE pressurizing the system fill system with smoke using special tool KLI9210 and adapter KLI9210/50.
  • An ultrasonic detector may also be used to detect extremely small leaks where smoke may not be visible.

Special tool KLI9210 (Evaporative system leak detector), connecting to 1.8L Turbo 

• Install optional fitting LKI9210/50 on hose of special tool KLI9210.
• Connect KLI9210 to VAG 1687/1 adapter (KLI9210 is shown attached to VAG 1687/1 at arrow on 1.8L Turbo).
  Fig 5: Connecting KLI9210 To VAG 1687/1 Adapter (1.8L Turbo)

  Courtesy of AUDI OF AMERICA, INC.

Special tool KLI9210 (Evaporative system leak detector connecting to 2.7L BiTurbo 

• Install optional fitting LKI9210/50 on hose of special tool KLI9210.
• Connect KLI9210 to VAG 1687/1 adapter (KLI9210 is shown attached to VAG 1687/1 at arrow on 2.7L BiTurbo).
  Fig 6: Connecting KLI9210 To VAG 1687/1 Adapter (2.7L BiTurbo)

  Courtesy of AUDI OF AMERICA, INC.

Special tool LKI9210 (Evaporative system leak detector), preliminary set-up 

• Connect smoke generator leads to vehicle battery.
• Turn valve to test -black arrow-.
  Fig 7: Turning Valve To Test -Black Arrow-

  Courtesy of AUDI OF AMERICA, INC.
• Press smoke generator button to fill system with smoke (see instructions printed on tester).

With system filled with smoke:

• Remove smoke generator hose and connect VAG1687 quickly to prevent smoke from leaking out. See EXHAUST SYSTEM COMPONENTS, REMOVING AND INSTALLING .

Special tool VAG 1687, connecting to pressure adapter VAG 1687/1 (1.8L Turbo) 

For illustrations purposes VAG is shown lying in the engine compartment. In practice the tool should be hung from the hood.

• Connect VAG 1687 quickly to prevent smoke from leaking out.
  Fig 8: Connecting VAG 1687 To Prevent Smoke From Leaking Out (1.8L Turbo)

  Courtesy of AUDI OF AMERICA, INC.

  VAG 1687 is shown connected to VAG 1687/1 -black arrow-

  Shop air supply will be connected to VAG 1687 -at white arrow-

• Perform pressure test. See PERFORMING PRESSURE TEST .

Special tool VAG 1687, connecting to pressure adapter VAG 1687/1 (2.7L BiTurbo) 

For illustrations purposes VAG is shown lying in the engine compartment. In practice the tool should be hung from the hood.

• Connect VAG 1687 quickly to prevent smoke from leaking out.
  Fig 9: Connecting VAG 1687 To Prevent Smoke From Leaking Out (2.7L BiTurbo)

  Courtesy of AUDI OF AMERICA, INC.

  VAG 1687 is shown connected to VAG 1687/1 -black arrow-

  Shop air supply will be connected to VAG 1687 -at white arrow-

• Perform pressure test. See PERFORMING PRESSURE TEST .