Powertrain, generic (extended)

P2BCD Battery Charging System Negative Contactor B Stuck Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2BCD is set when negative charging contactor B fails to close, so the charging branch lacks its return path and no current can flow even with the plus side connected. No manufacturer documents P2BCD publicly; Mazda lists the welded minus case P2BCC and the non-closing plus case P2BC6 for the CX-90 PHEV, but not this one. GM's Volt test for positive contactor A (P0D09) illustrates how a non-closing contactor shows up: with the charging and precharge contactors commanded on, the charger-side voltage stays below 10 V, and 8 failures in 9 samples end the check. Under CARB rules the charging hardware of plug-in vehicles must be supervised. Typical causes are burnt or contaminated contacts, a weak coil supply and module software. P2BCC is the welded variant, P2BC6 the plus side, P0D10 the contactor A twin. Charging aborts.

Likely causes

Negative contactor B burnt or mechanically not closing
Coil supply too weak or interrupted
Charging control software misjudging the check

Symptoms

  • Charging stops or never starts
  • Charging fault message

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–4,000
Time0–10 h

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

Parts involved

bcs neg contactor bwiring harnessbms

Related codes

P2BCBP2BCCP2BCEP2BC6P0D10

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.