Powertrain, generic (extended)

P2D76 Battery Charging System Negative Contactor D Control Circuit High

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

P2D76 means the control wire of minus contactor D shows more voltage than the module asked for. No manufacturer documents P2D76 publicly. GM's 2016 test for the minus charge contactor (P0D11) flags a power short when the idle output gets within 0.4 V of the supply. The effect hinges on which coil end is switched, which a GM patent leaves open: on a ground-side switched coil, a short to supply at the switched end means both coil ends sit at the same potential, so contactor D never pulls in and the driver may see overcurrent when it turns on; on a supply-side switched coil the contactor may close by itself. Either way charging via path D stops. P2D75 is the low case, P2D6F the plus side, P2D68 contactor C.

Likely causes

Drive wire of contactor D touching a 12 V feed

Output stage that no longer switches off

Crossed wires after work on the battery

Symptoms

Charging mode via contactor D blocked
Fault appears as soon as ignition is on
Charging or high-voltage warning

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€100–1,500

Time1–5 h

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

Parts involved

bcs neg contactor dwiring harnessbms

References: gsi.ext.gm.com, patents.google.com.