Turbocharger and wastegate bypass regulator valve, testing

Special tools, testers and auxiliary items

Fig 1: Identifying Turbocharger Tester V.A.G 1397A

Courtesy of VOLKSWAGEN UNITED STATES, INC.

V.A.G 1397 A

Fig 2: VAS 5051 Vehicle Diagnosis, Testing & Information System

Courtesy of VOLKSWAGEN UNITED STATES, INC.

VAS 5051 with VAS 5051/1

Malfunction reader V.A.G 1551 with V.A.G 1551/3 A

Requirements for test:

All hoses and lines must be securely installed and free of leaks.
DTC memory has been interrogated

Refer to

01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

; checking and erasing DTC memory

Output Diagnostic Test Mode has been performed

Refer to

01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

; Output Diagnostic Test Mode

Vehicle diagnostic, testing and information system VAS 5051 or malfunction reader V.A.G 1551 must be connected.

Test sequence

WARNING:

To avoid any risk of accident, observe the safety precautions when using test instruments while road testing the vehicle. Refer to Safety precautions

Fig 3: Connecting T-Piece And Measuring Hose Of Turbocharger Tester V.A.G 1397 A To Intake Manifold

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Connect T-piece and measuring hose of turbocharger tester V.A.G 1397 A to intake manifold (front).
Route measuring hose under rear edge of hood and into passenger compartment via right-hand window.

Fig 4: Identifying Turbocharger Tester V.A.G 1397 A

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Switch on turbocharger tester and set measuring range selector switch to position -I- (absolute pressure).
Connect measuring hose to connection -I-.

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 the last measured value until memory key M is pressed again or tester is switched off.
The decimal point in the display flashes to indicate that the value is being stored.
If the battery voltage of the turbocharger tester drops below the minimum level, an arrow will appear at the top left of the display.
Before performing the test, drive the vehicle at a brisk speed for at least 3 km (without stopping at traffic lights etc.).
A second mechanic is required to note the readings on the tester when the vehicle is moving.

Rapid data transfer HELP
Select function XX

Indicated on display:

Enter "08" to select the function "Read measured value block" and confirm entry with Q key.

Read measured value block Q
Enter display group number XXX

Indicated on display:

Enter "004" to select Display Group 004 and confirm entry with Q key.

Read measured value block 4 →
1 2 3 4

Indicated on display:

Do not proceed with the test until the intake air temperature shown in display zone 4 is between 20 and 50° C. If necessary, run the engine until the required temperature is reached.

Press C key.

Read measured value block Q
Enter display group number XXX

Indicated on display:

Enter "115" to select Display Group 115 and confirm entry with Q key.

Read measured value block 115 →
1 2 3 4

Indicated on display: (1-4 = display zones)

Accelerate the vehicle from 2000 RPM in 4th gear and observe the rev counter.
When the engine speed reaches 3000 RPM, press the "PRINT" key on VAS 5051 (or V.A.G 1551) and at the same time press the memory key "M" on V.A.G 1397 A.

NOTE: The charge air pressure should be measured using turbocharger tester V.A.G 1397/A. Vehicle diagnostic, testing and information system VAS 5051 (or malfunction reader V.A.G 1551) is used to check whether the charge pressure is being registered by the control module.

Fig 5: Identifying Turbocharger Tester V.A.G 1397 A

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Specification on V.A.G 1397 A: 1.700 - 2.000 bar

Fig 6: Identifying Turbocharger Tester V.A.G 1397 A

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Specification on VAS 5051 or V.A.G 1551

Display zone 4: 1700 - 2000 mbar

If specification not attained or exceeded:

Interrogate DTC memory of engine control module.

Refer to

01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMU
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): ATC
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AWP
01 ON BOARD DIAGNOSTIC (OBD) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): BEA

; checking and erasing DTC memory

Malfunctions in charge air pressure control function

Malfunction

Charge air pressure

Possible cause of malfunction

Charge air pressure too low

Measured value less than 1.700 bar or 1700 mbar

Wastegate bypass regulator valve -N75- defective
Fault in wiring to Wastegate bypass regulator valve

Wastegate bypass regulator valve in turbocharger is sticking in the "open" position
Leak between turbocharger and intake manifold

Charge pressure bypass valve defective
Turbocharger defective

Charge air pressure too high 1)

Measured value higher than 2.000 bar or 2000 mbar

Pressure unit for Wastegate bypass regulator valve defective
Air leaks in hoses or connections to pressure unit for charge air pressure control (via -N75-)

Wastegate bypass regulator valve in turbocharger sticking in closed position

1) If the charge air pressure is too high the fuel supply will be interrupted in order to protect the engine. This results in misfiring at high engine speeds.