Checking function of vacuum system (N55T0 Engine) (2016-2018)

CAUTION: Note the sequence of the diagnosis instructions in the ISID:
Depending on the fault pattern, the order of operations in the repair instructions may be different from the order of operations in the ISID .

Carry out procedure to check the vacuum system.

Check the function of the vacuum pump:

Press and pull off the lock of the vacuum line (1) (see arrows in illustration).

NOTE: This empties the vacuum reservoir, this will always be accompanied by a sucking noise.

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Check suction effect of vacuum pump .

Connect vacuum line (1) and the Integrated Measurement Interface Box with the vacuum hose (2) (Integrated Measurement Interface Box accessories) 81 31 2 468 782 (previously: 81 31 2 357 800 or 81 38 2 201 924).

Start engine.

Run engine at idle speed.

Follow diagnosis instruction.

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Check vacuum reservoir .

Reconnect vacuum line from vacuum pump to the vacuum reservoir.

NOTE: When the IMIB (1) is used the absolute pressure is displayed.

Follow diagnosis instruction.

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Pull off connection (1) at the vacuum reservoir to the exhaust flap.

Pull off connection (2) at the vacuum reservoir to the EPDW (pressure converter).

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Check vacuum reservoir .

Seal connection on vacuum reservoir with sealing cap (1).

Connect the vacuum reservoir and the Integrated Measurement Interface Box with the vacuum hose (Integrated Measurement Interface Box accessories) 81 31 2 468 782 (previously: 81 31 2 357 800 or 81 38 2 201 924).

Follow diagnosis instruction.

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Functional check of exhaust flaps (if installed) .

Checking function of exhaust flap (1).

Follow diagnosis instruction.

Illustration shows E81.

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Check suction operation on the exhaust flap .

Pull off the vacuum line to the EPDW at the vacuum reservoir and seal the connection at the vacuum reservoir with sealing cap (1).

Pull off vacuum line (2) to the exhaust flap and connect it to the vacuum hose (Integrated Measurement Interface Box accessories) 81 31 2 468 782 (previously: 81 31 2 357 800 or 81 38 2 201 924) and the vacuum reservoir by means of a T-connecting element.

NOTE: When the IMIB is used the absolute pressure is displayed.

Follow diagnosis instruction.

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Leakage test of vacuum line to exhaust flap .

Disconnect vacuum line (1) with pliers (2) as shown in the illustration.

Follow diagnosis instruction.

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Check function of wastegate valve .

Initial setting of wastegate linkage (1).

Observe wastegate linkage (1); it must close following activation (arrows in illustration).

Follow diagnosis instruction.

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Pressure converter connections

Disconnect vacuum hose at connection (VAC = vacuum reservoir).

Disconnect vacuum hose at connection (OUT= turbocharger vacuum unit).

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Leakage test of hoses to wastegate valve .

Pull vacuum line off pressure converter plug connection (OUT).

Pull vacuum line off pressure converter plug connection (VAC).

Connect both vacuum lines and the vacuum hose (Integrated Measurement Interface Box accessories) 81 31 2 468 782 (previously: 81 31 2 357 800, or 81 38 2 201 924) by means of a T- connecting element (1).

Follow diagnosis instruction.

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NOTE: Remove all special tools.
Reassemble the vehicle.