Powertrain, generic

P0EFD Battery Charger A Input Voltage Sensor C Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0EFD reports that the reading of input voltage sensor C in charger A sits below its plausible band. No manufacturer documents P0EFD publicly. GM's 2011 Volt charger module gives a reference for sensor A: once AC is detected at the inlet, a peak value under 90 V for 1500 ms within a 1875 ms window sets P0D3F, Type A with the warning lamp after one trip. Causes on the measuring side are a short to ground on the sense path, a shorted lower divider resistor or a missing reference for the converter. A phase that is genuinely dead at the supply, such as a tripped breaker on one leg of a three-phase station, can produce the same picture, so the incoming voltage is measured first. Mains undervoltage proper has its own codes such as P0D27; the high counterpart is P0EFE.

Likely causes

Defective divider or converter input for channel C in the charger
One phase missing at the supply (tripped breaker or fault in the station or cable)
Sense path of channel C shorted to ground

Symptoms

  • AC charging refused right after plugging in
  • Charging works on a different station or outlet
  • Charging fault message

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€0–2,500
Time0.3–4 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

P0EFEP0EFBP0EFCP0EF9P0D3FP0D27

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