000175 / P000175

000175 / P00AF - Alternator Module for Turbocharger 1: Stuck

Possible Symptoms

  • Malfunction Indicator Light (MIL) on

  • Glow plug light flashing

  • Reduced engine performance


Possible Causes

  • Defective N75

  • N75 connector plugged into the wrong two wire component. Refer to wiring diagram to verify

  • Vacuum leak or low vacuum

  • VNT sticking or seized

  • G581 sensor


Possible Solutions

  • Verify N75 is working to design, use output testing

  • Verify the N75 connector plugged into N75 per the factory level wiring diagram rather than any other component that may not set a fault code such as N79 (Positive Crankcase Ventilation (PCV) heating element)

  • Verify vacuum lines are good, check engine vacuum at idle

  • Test VNT and G581, apply vacuum to VNT and watch MVB 120.4

  • Engine off, no vacuum 120.4 should read about 3.5V

  • Engine Off, apply 17 Inches of mercury, 120.4 should drop to about .7V

  • Engine at idle, 120.4 should read about .7V

  • If 120.4 voltage does not alter, VNT may be seized or G581 failed

Special Notice

  • On some TDI engines, the vacuum diaphragm / G581 unit can be purchased as a separate part from dealer.

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