Checking the solenoid valve for boost pressure control — AUDI

AJL
Testing operation

Pull the hoses off the (N75) solenoid valve for boost pressure control=> Fitting locations -Overview - Page
24-5
.
Connect auxiliary hose.
Start the final control diagnosis and actuate the (N75) solenoid valve for boost pressure control =>Page
01-39
.

Final control diagnosis
⇒
Boost pressure control solenoid valve -N75 defective
Display readout:

The valve should click...
... ...and should open and close (check by blowing into the auxiliary hose).

If the valve does not click:

Check the solenoid valve for boost pressure control electrically => Page
24-38
.

When there is no electrical signal, the long connection is closed.

If the solenoid valve clicks, but does not open and close properly:

Replace boost pressure control solenoid valve (N75).

Electrical check on solenoid valve for boost pressure control (N75).

Withdraw the connector from the valve => Fitting locations -Overview - Page
24-5
.
Connect the V.A.G 1526 hand held multimeter for resistance measurement to the valve.

Specification: 25...35 ω

If the specification is not obtained:

Replace boost pressure control solenoid valve (N75).

If the specification is obtained:

Check the power supply from the solenoid valve for boost pressure control => Page
24-39
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Check the power supply to the solenoid valve for boost pressure control (N75)

Connect the V.A.G 1526 hand held multimeter for voltage measurement to contact 1 of the and to the earth.
Operate the starter briefly (the engine may also start briefly).

Specification: approx. battery voltage

If the specification is not obtained:

Check the wiring from contact 1 on the connector via the fuse to the fuel pump relay for an open circuit or short circuit.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations

If the specified value is achieved:

Check the actuation for the solenoid valve for boost pressure control => Page
24-40
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Checking the actuation of the solenoid valve for the boost pressure control (N75)

Unplug the connector from the solenoid valve (N75) and connect the V.A.G 1527 diode test lamp between connector contacts 1 and 2.
Start the final control diagnosis and actuate the N75 solenoid valve for boost pressure control =>Page
01-39
.

diode test lamp should start flashing.

If diode test lamp does not flash or if the lamp is lit continuously. Check the wiring.

Connect test box V.A.G 1598/22 to wiring harness for engine control unit =>Page
24-7

The following wiring connection is to be examined for open circuits and/or short to positive or negative.

2-pin connector on wiring harness, contact · Test box V.A.G 1598/22 contact
2 · 64

Rectify short circuit or open circuit if necessary.