Intake system, checking for leaks using V.A.G 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

Fig 1: Checking Charge Air Pressure System Using V.A.G 1687 Charge Air System Tester

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Check the charge air pressure system using the V.A.G 1687 Charge air system tester.

Special tool V.A.G 1687 Charge air system tester preliminary set-up

Fig 2: Special Tool V.A.G 1687 Charge Air System Tester Preliminary Set-Up

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Back off pressure regulator knob -2- of V.A.G 1687 fully to protect gauge when shop air supply is applied to assembly.
Close valve -3- before gauge.
Close valve -4- after gauge.

The shop air supply line will later be attached to the inlet of V.A.G 1687.

Remove female fitting from tester (arrow) and install an appropriate "male" air fitting that will connect to your shop air supply line (Refer to WARNING!).

WARNING:

Use only approved air fittings to adapt shop air supply line to V.A.G 1687 tester.

Special tool V.A.G 1687/1 pressure adapter, installing (1.8L Turbo)

Separate intake hose from Mass Air Flow (MAF) sensor assembly.

Fig 3: Special Tool V.A.G 1687/1 Pressure Adapter, Installing (1.8L Turbo)

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Insert V.A.G 1687/1 pressure adapter in intake hose (black arrow) using existing clamp (as shown).
Remove crankcase ventilation tube from intake hose at (white arrow).

Special tool V.A.G 1687/1 pressure adapter, installing (2.7L BiTurbo)

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

Refer to 01 MAINTENANCE ; Air cleaner housing, cleaning; Air cleaner element, replacing

Fig 4: Special Tool V.A.G 1687/1 Pressure Adapter, Installing (2.7L BiTurbo)

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Insert V.A.G 1687/1 pressure adapter in intake hose (white arrow) using existing clamp (as shown).
Disconnect engine crankcase ventilation hose from intake manifold (black arrow).
Plug intake manifold fitting (for crankcase ventilation hose) with appropriate hose and metal plug using clamps supplied with V.A.G 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 as described on. Refer to Intake system, checking for leaks using V.A.G 1687 Diagnostic Tool .
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 KLI9210/50 on hose of special tool KLI9210.

Fig 5: Special Tool KLI9210 (Evaporative System Leak Detector), Connecting To 1.8L Turbo

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Connect KLI9210 to V.A.G 1687/1 adapter (KLI9210 is shown attached to V.A.G 1687/1 at arrow on 1.8L Turbo).

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

Install optional fitting KLI9210/50 on hose of special tool KLI9210.

Fig 6: Special Tool KLI9210 (Evaporative System Leak Detector), Connecting To 2.7L BiTurbo

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Connect KLI9210 to V.A.G 1687/1 adapter (KLI9210 is shown attached to V.A.G 1687/1 at arrow on 2.7L BiTurbo).

Special tool KLI9210 (Evaporative system leak detector), preliminary set-up

Connect smoke generator leads to vehicle battery.

Fig 7: Special Tool KLI9210 (Evaporative System Leak Detector), Preliminary Set-Up

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Turn valve to test -black arrow-.
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 V.A.G1687 quickly to prevent smoke from leaking out (Refer to Intake system, checking for leaks using V.A.G 1687 Diagnostic Tool ).

Special tool V.A.G 1687, connecting to pressure adapter V.A.G 1687/1 (1.8L Turbo)

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

Connect V.A.G 1687 quickly to prevent smoke from leaking out.

Fig 8: Special Tool V.A.G 1687, Connecting To Pressure Adapter V.A.G 1687/1 (1.8L Turbo)

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V.A.G 1687 is shown connected to V.A.G 1687/1 (black arrow)

Shop air supply will be connected to V.A.G 1687 at (white arrow)

Perform pressure test (Refer to Performing pressure test: ).

Special tool V.A.G 1687, connecting to pressure adapter V.A.G 1687/1 (2.7L BiTurbo)

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

Connect V.A.G 1687 quickly to prevent smoke from leaking out.

Fig 9: Special Tool V.A.G 1687, Connecting To Pressure Adapter V.A.G 1687/1 (2.7L BiTurbo)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

V.A.G 1687 is shown connected to V.A.G 1687/1 (black arrow)

Shop air supply will be connected to V.A.G 1687 at (white arrow)

Perform pressure test (Refer to Performing pressure test: ).