With Manufacturer's Scan Tool

Wastegate bypass regulator valve -N75-, checking
Special tools and equipment





^ VAG 1526 A
^ VAG 1527 B
^ VAG 1594 A
^ VAG 1598/31
^ VAS 5051 with VAS 5051/1
or
^ VAG 1551 with VAG 1551/3 A

Test requirement:
^ Vehicle Diagnostic, Testing and Information System VAS 5051 or VAG 1551 Scan Tool must be connected.

Test sequence

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

^ Read out DTC memory of engine control module.
If display shows a DTC relating to wastegate bypass regulator valve -N75-:
^ Disconnect hoses from valve; leave connector attached.





^ Connect test hose to valve connection marked with arrow.
^ Start Output Diagnostic Test Mode and actuate 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
^ Unplug connector at valve.





^ Connect multimeter and measure resistance at valve.
^ Specification: 25.to 35 rat
If reading does not match specification:
^ Replace wastegate bypass regulator valve -N75-.
If measured value matches specification:
^ Check power supply.

Checking power supply
Test requirements:
^ Fuse for wastegate bypass regulator valve OK
^ Fuel pump relay OK








^ Connect voltage tester VAG 1527 B as follows:
^ 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:
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations
^ 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-.





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 the following wiring connection:
^ If necessary, eliminate open circuit/short circuit.
If wiring is OK:
^ Replace engine control module.