Powertrain, generic

P0EFB Battery Charger A Input Voltage Sensor C Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0EFB flags an electrical fault on the third AC input voltage channel of on-board charger A, sensor C. Channel A reports through P0D3D to P0D41, channel B through P0EF7 to P0EFA; a third channel fits chargers that read each phase of a three-phase supply separately. This is the catch-all circuit code, used when the signal is unusable without being sorted into range, low or high (P0EFC, P0EFD, P0EFE). No manufacturer documents P0EFB publicly, and GM's hybrid tables for 2011, 2012 and 2014 to 2019 never list the matching circuit code P0D3D either, catching wiring faults on sensor A only through its low and high checks. In TI's 11 kW reference design every phase is scaled by a resistor chain and centred at 1.65 V in a 3.3 V converter, so a dead channel is easy to spot. AC charging is refused or limited.

Likely causes

Failed measuring channel C on the charger board (divider, amplifier or converter input)
Open or loose sense connection for this phase inside the charger or at the AC inlet harness
Charger software marking a valid channel as faulty

Symptoms

  • AC charging does not start or is limited
  • Possible reduced charging power on three-phase stations
  • Charging fault shown in the cluster or app

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–2,500
Time0.5–4 h

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

Parts involved

battery charger a input voltage sensor cwiring harnesson board charger

Related codes

P0EFCP0EFDP0EFEP0EF7P0D3D

References: law.cornell.edu, gsi.ext.gm.com, ti.com.