P1600 — Volkswagen — Power Supply Terminal No 15 Low Voltage

P1600 (Volkswagen): Power Supply Terminal No 15 Low Voltage — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Power Supply Terminal No 15 Low Voltage. Source catalogue definition; confirm applicability using vehicle service information.

Affected system: Powertrain

Symptoms

  • Engine fails to start
  • Dashboard warning lights illuminated
  • Intermittent loss of power
  • ECU communication errors
  • Stored ignition switch performance codes

Possible causes

  • Faulty ignition switch contact
  • Blown fuse for ignition circuit
  • Corroded wiring at Terminal 15 relay
  • Loose battery ground connection
  • Defective engine control module relay

What to check

  • Inspect the ignition switch for proper electrical continuity
  • Test the ignition circuit fuse for electrical integrity
  • Measure voltage at Terminal 15 with the ignition in the ON position
  • Check the engine control module relay for proper switching
  • Examine wiring harness connections for signs of corrosion or damage