Wastegate Bypass Regulator Valve -N75-

z Valve is activated (pulsed) by the Engine Control Module (ECM)

z Closed when no voltage present, limits charge pressure

Engine code APH

z At 3000 RPM, press the "M" memory button on turbocharger tester and read out the test value.

Specified value: (absolute pressure)

1.300... 1.750 bar

Engine code AWP

z Between 1800 to 2300 RPM, press the "M" memory button on turbocharger tester and read out the test

value.

Specified value: (absolute pressure)

1.350... 2.000 bar

Engine code AWV

z Between 1800 to 2300 RPM, press the "M" memory button on turbocharger tester and read out the test

value.

Specified value: (absolute pressure)

1.350... 1.750 bar

If boost pressure is exceeded:

z Check the Charge Air Pressure Sensor -G31-, see CHARGE AIR PRESSURE SENSOR,

CHECKING .

z Check Wastegate Bypass Regulator Valve - N75-. (Throughput in hose from turbocharger via valve to

vacuum diaphragm with connector disconnected), see WASTEGATE BYPASS REGULATOR

VALVE, CHECKING .

z Check for proper seating of vacuum diaphragm for wastegate bypass regulator valve at turbocharger.

z Check vacuum diaphragm, see VACUUM DIAPHRAGM FOR WASTEGATE BYPASS

REGULATOR VALVE, CHECKING

z Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If

rusted solid, replace turbocharger.

z Replace turbocharger, see item no. 6

z Erase DTC memory of Engine Control Module (ECM), see DIAGNOSTIC MODE 4: RESET/ERASE

DIAGNOSTIC DATA .

z Generate readiness code, see READINESS CODE, GENERATING .

If boost pressure is not reached:

z Check the Charge Air Pressure Sensor -G31-, see CHARGE AIR PRESSURE SENSOR,

CHECKING .

z Check Wastegate Bypass Regulator Valve - N75-, see WASTEGATE BYPASS REGULATOR

VALVE, CHECKING .

z Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If

rusted solid, replace turbocharger.

z Replace turbocharger, see item no. 6

z Erase DTC memory of Engine Control Module (ECM), see DIAGNOSTIC MODE 4: RESET/ERASE

DIAGNOSTIC DATA .

z Generate readiness code, see READINESS CODE, GENERATING .

Disconnect connector -2- at Wastegate Bypass Regulator Valve -N75

Measure resistance between terminals of valve.

Specified value: 25...35 ohm

If specified value is not obtained:

z Replace Wastegate Bypass Regulator Valve -N75-

z Vehicles with engine code APH, see item 17 ,

z Vehicles with engine code AWP, AWV, see item 22

Disconnect 4-pin connector -2- from Charge Air Pressure Sensor -G31- (-1-).

Fig. 11: Disconnecting 4-Pin Connector From Charge Air Pressure Sensor

Use adapter cables from (VAG1594) to connect multimeter to terminals 1 + 3 of connector for voltage

measurement.

z Switch ignition on.

Specified value: at least 4.5 V

z Switch ignition off.

If there is no voltage:

Measuring Voltage Between Charge Air Pressure Sensor Harness Connector Terminals 1

And 3

Check for open circuits in wires between test box and connector according to wiring diagram.

Terminal 1+socket 108

Terminal 3 + socket 98

Terminal 4 + socket 101

Wire resistance: max. 1.5 ohm

Re-connect connector at Charge Air Pressure Sensor -G31-.

z Use adapter cables from VAG1594 to connect multimeter to sockets 101 (B+) + 108 (Ground -GND-) for

voltage measurement.

z Start engine and measure voltage.

Specified value: 1.80 to 2.00 volts

z Bring engine to RPM by depressing accelerator pedal suddenly.

Specified value: 2.00 to 3.00 volts

If specified values are not obtained:

z Replace Charge Air Pressure Sensor -G31-, see item 3

Recirculating valve for turbocharger, checking

Valve opens between connection to intake manifold and connection to deceleration shut-off valve with no

voltage. Connection to vacuum reservoir is closed.

Test sequence

z Switch ignition off.

z Disconnect connector from Recirculating valve for turbocharger -N249-.

z Measure resistance between terminals of valve.

Measuring Resistance Between Terminals Of Turbocharger Recirculating Valve

Specified value: 25...35 ohm

If specified value is not obtained:

z Replace Recirculating valve for turbocharger -N249-:

If specified values are obtained:

z Connect test box to control module wiring harness, see CONNECT TEST BOX FOR WIRING TEST .

z Check wire between test box socket 105+2-pin connector terminal 2 for open circuit according to wiring

diagram.

Wire resistance: max. 1.5 ohm

z Also check the wire for short circuit to B+ and Ground (GND).

If no malfunctions are found in wire:

z Check wire between 2-pin connector terminal 1 and the Fuel Pump (FP) Relay -J17- for open circuit

according to wiring diagram.

Wire resistance: max. 1.5 ohm

Vacuum diaphragm for wastegate bypass regulator valve, checking

Test requirements

z Coolant temperature must be at least 80 C, see DIAGNOSTIC MODE 1: CHECK MEASURED VALUES ; PID 5, Coolant temperature.

z No leaks on intake or exhaust side.

Test sequence

z Disconnect connector -2- at Wastegate Bypass Regulator Valve -N75- (-1-).

Start engine and increase speed to maximum RPM by depressing accelerator pedal suddenly. Operating

rod -2- for wastegate bypass regulator valve must move.

Identifying Bypass Regulator Valve Operating Rod

If operating rod does not move:

z Check lever for wastegate bypass regulator valve -1- for ease of movement. If rusted solid, replace

turbocharger.

If operating rod does not move despite freely moving lever:

z Replace turbocharger, see item no. 6

Deceleration shut-off valve, checking

Test sequence

z Connect hand vacuum pump (VAG1390) to vacuum connection for deceleration shut -off valve.

Fig. 19: Connecting Hand Vacuum Pump (VAG1390) To Deceleration Shut-Off Valve Vacuum Connection

Courtesy of VOLKSWAGEN OF AMERICA, INC.

z Operate vacuum pump.

Deceleration shut-off valve must open in direction of arrow

z Operate ventilation valve at vacuum pump.

NOTE: The deceleration shut-off valve is located in front of the turbocharger. It is opened by vacuum during deceleration and at idle.

Fig. 19: Connecting Hand Vacuum Pump (VAG1390) To Deceleration Shut-Off Valve Vacuum Connection

Courtesy of VOLKSWAGEN OF AMERICA, INC.

z Operate vacuum pump.

Deceleration shut-off valve must open in direction of arrow

z Operate ventilation valve at vacuum pump.

NOTE: The deceleration shut-off valve is located in front of the turbocharger. It is opened by vacuum during deceleration and at idle.

Deceleration shut-off valve must close

If deceleration shut -off valve does not open or does not close, replace valve, see VEHICLES WITH ENGINE CODE APH .

Disconnecting Connector From Wastegate Bypass Regulator Valve

Measure resistance between terminals of valve.

Specified value: 14...20 ohm

If specified value is not obtained:

z Replace Wastegate Bypass Regulator Valve -N75-.

If specified value is obtained:

Switch ignition on.

Measure voltage supply of valve at connector terminal 1 and at engine Ground (GND).

Specified value: approx. battery voltage