Body, generic

B0128 DC/AC Converter A High Voltage Power Outlet "B" Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0128 is the open-circuit fault for outlet B. Such a fault has to be told apart from a tripped protective device. In Ford's patent US11043801B2 each socket has a ground-fault interrupter whose breaker opens on a current imbalance and normally needs a manual reset; Ford adds an actuator so it can also be reset from a distance, plus test switches for the interrupters. Ford's SSM 49709 for the 2021 F-150 hybrid shows the everyday side: after the built-in Pro Power test the screen reports a ground fault until the reset button is pressed, which is normal behaviour. So rule out a tripped interrupter before chasing wiring. Where outlet B sits is not published, and no manufacturer documents B0128. Until repaired, socket B gives no power.

Likely causes

Feed to outlet B interrupted at a connector or in the harness
Ground-fault interrupter of outlet B defective or its reset actuator stuck
Moisture or dirt in socket B

Symptoms

  • Socket B dead, ground-fault or outlet message on the screen
  • Reset does not restore power to socket B
  • Outlet circuits carry 120/240 V AC from a high-voltage source; work only with the system de-energised

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

dc ac converter ahv outlet b

Related codes

B0127B0129B012AB012BB012C

References: patents.google.com, static.nhtsa.gov.