Powertrain, generic

P0E66 Battery Charger Control Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

With P0E66 the controller finds the charger command line pulled lower than the state it is driving, which typically means the wire touches ground somewhere between the control unit and the on-board charger. If the command is active-high, the charger simply never receives it; a grounded line can also overload the output stage that drives it. No manufacturer documents P0E66 publicly. GM's Volt and 2019 hybrid tables check this line only through the general code P0E65, based on a hardware fault flag sampled every 25 ms at 10.2 V or more. California's OBD rule requires plug-in hybrids to recognise charger faults that stop or limit charging. P0E67 is the opposite case, a line stuck high; P0E68 covers a line that is electrically sound but answers wrongly.

Likely causes

Control wire chafed through to body ground
Moisture in a connector bridging the signal to ground
Internal short in the charger's command input

Symptoms

  • Charging does not start after plugging in
  • Charge indicator shows a fault or goes out

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–500
Time0.5–3 h

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

Parts involved

battery charger control circuitwiring harnesson board charger

Related codes

P0E65P0E67P0E68P0E62

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