Wastegate Bypass Regulator Valve -N75-, Testing

Wastegate Bypass Regulator Valve -N75-, Testing







Special tools, testers and other equipment required
- V.A.G 1526 A
- V.A.G1527B
- V.A.G 1594 A
- V.A.G 1598/31
- VAS5051 with VAS 5051/1

or

- V.A.G 1551 with V.A.G 1551/3 A

NOTE: Wastegate bypass regulator valve -N75- and its wiring are monitored by the engine control module.

- Connect vehicle diagnostic, testing and information system VAS 5051 (or malfunction reader V.A.G 1551) and select engine electronics control module by entering "Address word" 01. When doing this the engine must be running at idling speed.

- Interrogate DTC memory of engine control module.

If the display shows a DTC relating to Wastegate bypass regulator valve -N75-:
- Disconnect hoses from valve but leave the electrical connector connected.
- Install an auxiliary hose to one of the connections on the valve.
- Start Output Diagnostic Test Mode and activate Wastegate bypass regulator valve -N75.

Indicated on display:
Output Diagnostic Test Mode ->
Charge air pressure control solenoid valve -N75-

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

Valve does not click:
- Test internal resistance of valve.

If the valve does not open and close properly:
- Replace Wastegate Bypass Regulator Valve -N75-.

Testing internal resistance

- Disconnect electrical connector from valve.







- Connect multimeter to valve (resistance measurement range)

- Specification: 25 - 35 Ohms

If the specification is not attained:
- Replace Wastegate Bypass Regulator Valve -N75-.

If the specification is obtained:

Testing voltage supply







- Connect voltage tester V.A.G 1527 B as follows:


Connector Contact Measure against
1 Engine Ground(GND)

- Operate starter briefly.
- The LED should light up.

If the LED does not light up:
- Test for open circuit in wiring from contact 1 to fuel pump relay via fuse.

- Correct any open circuits.

If the wiring is OK:
- Test fuel pump relay.

If the LED lights up:

Checking activation







- Connect voltage tester V.A.G 1527 B to contact 1 (positive) and contact 2 of the connector.
- Start Output Diagnostic Test Mode and activate Wastegate bypass regulator valve -N75-.

- The LED should flash.

If the LED lamp does not flash or lights up continuously:
- Connect test box V.A.G 1598/31 to wiring harness for engine control module. Do not connect the engine control module itself.







- Test for open circuit and short to positive or Ground (GND) in the following wiring connections:

Connector Contact Test box V.A.G 1598/31 Contact
1 104

- Rectify short circuit or open circuit if necessary.

If the wiring is OK:
- Replace engine control module.