With Manufacturer's Scan Tool

Wastegate Bypass Regulator Valve -N75-, Checking







Special tools and equipment
- VAG 1526 A Multimeter or equivalent
- VAG 1527 B Voltage tester
- VAG 1594 A Connector test set
- VAG 1598/31 Adapter
- VAS 5051 Vehicle Diagnostic, Testing and Information System VAS 5051 with VAS 5051/1
or
- VAG 1551 Scan Tool with VAG 1551/3 A

Requirement
- Vehicle Diagnostic, Testing and Information System VAS 5051 or VAG 1551 Scan Tool must be connected.

Work sequence

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

- Read DTC memory of engine control module.

If display shows a DTC relating to Wastegate bypass regulator valve -N75-:
- Disconnect hoses from valve; leave connector connected.







- Connect test hose to valve connection marked with (arrow).
- Start Output Diagnostic Test Mode and actuate Wastegate bypass regulator valve -N75-.

Output Diagnostic Test Mode ->
Wastegate bypass regulator valve -N75

Indicated on display
- Valve must click...
- ...and must open and close (can be checked by blowing into test hose).

If valve does not click:
- Check internal resistance of valve.

If valve does not open or close properly:
- Replace Wastegate bypass regulator valve -N75-.

Checking internal resistance
- Disconnect connector at valve.







- Connect multimeter and measure resistance at valve.

Specification: 25 to 35 Ohms

If reading does not match specification:
- Replace Wastegate bypass regulator valve -N75-.

If measured value matches specification:
- Check power supply.

Checking power supply
Requirements
- Fuse for wastegate bypass regulator valve OK
- Fuel pump relay OK







- Connect voltage tester VAG 1527 B as follows:

Connector Measure to
contact
1 Engine Ground

- Briefly operate starter.
- LED must light up

If LED does not light up:
- Check for open circuit in wiring from contact 1 of connector through fuse to fuel pump relay:
- If necessary, eliminate open circuit.

If LED lights up:
- Check actuation.

Checking actuation







- Connect voltage tester VAG 1527 B to contact 1 (positive) and 2 of connector.
- Start Output Diagnostic Test Mode and actuate Wastegate bypass regulator valve -N75-.

Output Diagnostic Test Mode ->
Wastegate bypass regulator valve -N75-

Indicated on display:
- LED must flash

If LED does not flash or if it is permanently lit:
- Connect test box VAG 1598/31 to engine control module wiring harness. Engine control module must not be connected.







- Check for open circuit and short to Ground/positive in following wiring connection:

Connector Test box VAG 1598/31
contact socket
2 104

- If necessary, eliminate open circuit/short circuit.

If wiring is OK:
- Replace engine control module.