Powertrain, generic (extended)

P2D68 Battery Charging System Negative Contactor C Control Circuit High

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

P2D68 means the wire energising minus charging contactor C carries more voltage than commanded, for instance where it rubs on a 12 V line or the output stage keeps conducting. No manufacturer documents P2D68 publicly. GM's published tests show how such a short is judged and how the margin has tightened: for the 2011 Volt minus charge contactor (P0D11) GM calls it a short to supply once the idle output comes within 1.2 V of the supply voltage; the 2016 tables cut that margin to 0.4 V. If the coil is fed from the high side, a short can pull contactor C in without command and close the return pole while the module thinks it is open, so charging is normally locked. P2D67 is the low case, P2D61 the plus side, P2D76 contactor D.

Likely causes

Drive wire chafed against a 12 V supply line

Output stage in the module no longer switches off

Wires swapped or pinched after repair work

Symptoms

Charging blocked as a precaution
Contactor may click without a charging request
High-voltage or charging 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 cwiring harnessbms

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