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2004 AUDI S4
4.2L V8•AWD•AUTOMATIC•gas•BBK
1 active safety recall on this vehicle — view recalls
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Repairs0Labor497Torque3159Fluid10DTC956Battery1Maintenance0Recalls1
U0184low severityNetwork

Lost Communication with Radio Module

on 2004 Audi S4 4.2L V8 · AWD

What this code means

Cannot communicate with the radio or entertainment system head unit.

Symptoms

  • Radio display blank
  • No audio
  • Infotainment system offline
  • Touchscreen not responding
  • Backup camera display not available

Common causes

  • Radio module failure
  • CAN bus wiring
  • Module power loss
  • Fuse blown
  • Software crash

Diagnostic steps

  1. Check radio fuse
  2. Test power and ground
  3. Check CAN wiring
  4. Try radio reset procedure
  5. Check for software update availability

Repair notes

Check fuses. Many head units can be reset by pulling the fuse for 30 seconds.

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