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2019 AUDI A6
3.0L V6 TFSI•AWD•AUTOMATIC•gas•supercharged
7 active safety recalls on this vehicle — view recalls
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Repairs0Labor495Torque4326Fluid9DTC1145Battery1Maintenance0Recalls7
P3800high severityPowertrain

48V Mild Hybrid System General Malfunction

on 2019 Audi A6 3.0L V6 TFSI · AWD

What this code means

The 48V mild hybrid system has detected a general fault preventing normal operation. The belt-driven starter-generator (BSG) and 48V battery are not functioning correctly.

Symptoms

  • Mild hybrid functions disabled
  • Increased fuel consumption
  • No electric boost assist
  • Coasting recuperation disabled
  • Start-stop not functioning
  • Engine feels less responsive

Common causes

  • 48V battery management fault
  • BSG control module error
  • 48V DC-DC converter failure
  • CAN communication error between modules
  • 48V wiring harness damage

Diagnostic steps

  1. Read 48V system fault codes
  2. Check 48V battery voltage and SOC
  3. Test BSG control module communication
  4. Inspect 48V wiring and connectors
  5. Monitor 48V system during engine start and coast

Repair notes

Diagnose and replace failed 48V component. System must be de-energized before service. 48V systems can cause burns and arc flash.

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