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2017 GMC ACADIA

2.5L I4•AWD•AUTOMATIC•gas
4 active safety recalls on this vehicle — view recalls
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Repairs0Labor564Torque4752Fluid9DTC969Battery0Maintenance0Recalls4
P3803high severityPowertrain

48V DC-DC Converter (48V to 12V) Fault

on 2017 GMC Acadia 2.5L I4 · AWD

What this code means

The DC-DC converter that steps down 48V to charge the 12V system and battery has a fault. In 48V systems, this converter often replaces the traditional alternator.

Symptoms

  • 12V battery not charging
  • Electrical accessories dimming
  • 12V battery warning light
  • Vehicle may not restart
  • Multiple low-voltage warnings
  • Infotainment resets

Common causes

  • DC-DC converter internal failure
  • 48V input voltage out of range
  • 12V output regulation failure
  • Cooling system issue for converter
  • Communication fault with BMS

Diagnostic steps

  1. Measure DC-DC converter 12V output
  2. Check 48V input voltage
  3. Monitor 12V battery charge state
  4. Test converter cooling fan
  5. Read converter internal fault codes

Repair notes

Replace 48V to 12V DC-DC converter. Charge or replace 12V battery if damaged by undervoltage.

Other Powertrain codes on this vehicle

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