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2019 AUDI A6
3.0L Turbo V6•AWD•AUTOMATIC•gas•turbo
7 active safety recalls on this vehicle — view recalls
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Repairs0Labor495Torque4351Fluid8DTC1145Battery1Maintenance0Recalls7
P3658moderate severityPowertrain

GDI Fuel Rail Pressure Oscillation Detected

on 2019 Audi A6 3.0L Turbo V6 · AWD

What this code means

The fuel rail pressure in the GDI system is oscillating beyond normal limits, indicating a control instability or mechanical issue in the high-pressure fuel system.

Symptoms

  • Check Engine Light
  • Engine vibration at idle
  • Fuel injector noise louder than normal
  • Idle quality degradation
  • Possible misfire symptoms
  • Fuel smell intermittent

Common causes

  • HP fuel pump volume control valve hunting
  • Fuel rail pressure sensor noise
  • Pressure damper failure in fuel rail
  • Fuel injector leak causing pressure drops
  • HP pump cam follower uneven wear

Diagnostic steps

  1. Monitor fuel rail pressure waveform with fast data rate
  2. Check HP pump volume control solenoid
  3. Inspect pressure damper in fuel rail
  4. Test fuel injectors for leak-back
  5. Inspect HP pump cam follower for uneven wear

Repair notes

Replace pressure damper if failed. Service volume control solenoid. Replace cam follower if showing uneven wear.

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🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
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