Powertrain, generic (extended)

P2BD0 Battery Charging System Negative Contactor B Control Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

With P2BD0 the coil drive line of minus-side charging contactor B is too low – usually insulation damage letting the wire touch the body, or an output stage stuck low. Starved of current, the coil leaves the return path of that charging branch open. No manufacturer documents P2BD0 publicly. GM states that its open-circuit test (P0D11) on the Volt and ELR minus contactor A cannot see a short to ground, so that case has to be caught elsewhere. CARB obliges makers of plug-in vehicles to check this hardware. Look for chafed wiring along the battery tray or underbody, moisture in connectors and an internally shorted coil. The high counterpart is P2BD1, the plus side P2BC9, the contactor A twin P0D13. The vehicle will normally not charge in that mode.

Likely causes

Control wire of negative contactor B shorted to ground
Moisture in a connector of the control line
Coil of negative contactor B internally shorted

Symptoms

  • Charging session will not start
  • Charging fault message

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 bwiring harnessbms

Related codes

P2BCEP2BCFP2BD1P2BC9P0D13

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