With Manufacturer's Scan Tool

Wastegate Bypass Regulator Valve N75, Checking







Special tools, testers and auxiliary items required
- Multimeter VAG1526A or equivalent
- Voltage tester VAG1527B
- Connector test set VAG1594A
- Adapter VAG1598/31
- Vehicle Diagnostic, Testing and Information System VAS5051 VAS5051 with VAS5051/1
or
- Scan Tool VAG1551 with VAG1551/3A

Requirement
- Vehicle Diagnostic, Testing and Information System VAS5051 or Scan Tool VAG1551 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 .

Indicated on display:
Output Diagnostic Test Mode -->
Wastegate bypass regulator valve -N75

- 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 VAG1527B as follows:

Connector contact Measure to
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 VAG1527B to contact 1 (positive) and 2 of connector.
- Start Output Diagnostic Test Mode and actuate Wastegate bypass regulator valve N75 .

Indicated on display:
Output Diagnostic Test Mode -->
Wastegate bypass regulator valve -N75-

- LED must flash

If LED does not flash or if it is permanently lit:
- Connect test box VAG1598/31 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 contact Test box VAG1598/31 socket
2 104

- If necessary, eliminate open circuit/short circuit.

If wiring is OK:
- Replace engine control module.