Test sequence

Remove air filter housing. See REMOVING .
Connect T-piece and measuring hose of turbocharger tester V.A.G 1397 A to fuel pressure regulator connecting hose.

Fig 1: Connecting T-Piece And Measuring Hose Of Turbocharger
Courtesy of AUDI OF AMERICA, INC.
Route measuring hose under rear edge of hood and into passenger compartment via right-hand window.
Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure).

Fig 2: Identifying Switch On Turbocharger Tester
Courtesy of AUDI OF AMERICA, INC.
Connect measuring hose to connection -I-.
Install air filter housing. See INSTALLING .

NOTE:

Hose connections must be completely airtight, otherwise measurements will not be correct.
Ensure that measuring hose is not pinched at hood or side window.
Pressing memory key M on turbocharger tester will store last measured value until memory key M is pressed again or tester is switched off.
Decimal point in display flashes to indicate that value is being stored.
If battery voltage of turbocharger tester drops below minimum level, an arrow will appear at top left of display.
Before performing test, drive vehicle at a brisk speed for at least 3 km (without stopping at traffic lights etc.).

Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" from menu. When doing this engine should be idling.
See VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS 5051, CONNECTING AND SELECTING FUNCTIONS .

WARNING:

Test equipment must always be secured on rear seat and operated from rear seat by a second person.
If test equipment is operated from front passenger seat, occupant could be injured by passenger's airbag in an accident.

Display on VAS 5051:

Fig 3: Display On VAS 5051 - Charge Pressure Regulating Valve, Checking (1 Of 3)

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Select diagnosis function "08 - Read data block" from menu -1-.

Display on VAS 5051:

Fig 4: Display On VAS 5051 - Charge Pressure Regulating Valve, Checking (2 Of 3)

Courtesy of AUDI OF AMERICA, INC.

1 - Enter display group

Using keypad -2-, enter "115" to select "Display group 115" and confirm entry with Q button.
Take vehicle for a test drive.
Change to Tiptronic gear "4" at approx. 50 km/h.
Accelerate vehicle at full throttle (do not operate kick-down), and have a second mechanic watch rev counter.
When engine speed reaches approx. 2600 rpm, second mechanic presses "PRINT" key on VAS 5051 and at the same time memory key -M- on V.A.G 1397 A.

NOTE: Charge pressure should be measured using turbocharger tester V.A.G 1397/A. Vehicle diagnostic, testing and information system VAS 5051 is used to check whether charge pressure is being registered by control module.

Specification for V.A.G 1397 A: 1.500 ... 1.800 bar

Fig 5: Identifying V.A.G 1397 A

Courtesy of AUDI OF AMERICA, INC.

Specification for VAS 5051 in display zone -4-:1500 to 1800 mbar

Press the < button. See Fig 6.

Fig 6: Display On VAS 5051 - Charge Pressure Regulating Valve, Checking (3 Of 3)

Courtesy of AUDI OF AMERICA, INC.

If specification is not attained:

Check whether turbochargers operate uniformly. See CHECKING UNIFORM OPERATION OF TURBOCHARGERS .
Detect cause of malfunctions according to fault table. See FAULTS IN CHARGE PRESSURE CONTROL FUNCTION .