Powertrain, generic (extended)

P2BCB Battery Charging System Negative Contactor B Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2BCB is the general electrical code for negative contactor B of the charging system, which closes the return path of the second charging branch to the traction battery. No manufacturer documents P2BCB publicly. Where B serves DC fast charging, each pole usually has its own contactor so the inlet is isolated from the pack whenever no charger is connected; a Hyundai patent on quick-charge relays tests the plus and minus relay one after the other for exactly that reason. A Ford patent swaps the order in which the two charger contactors close from one session to the next and checks the last one closed for welding first. CARB requires monitoring of charging components on plug-in vehicles. Stuck closed and open are P2BCC/P2BCD, driver faults P2BCE–P2BD1, the plus side P2BC4, contactor A minus P0D0E.

Likely causes

Coil of negative contactor B open or shorted
Wiring or connector fault on the return-side contactor
Fault in the module that drives contactor B

Symptoms

  • Charging in the affected mode refused
  • Charging fault message
  • Driving usually still possible

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–1,800
Time1–6 h

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

Parts involved

bcs neg contactor bwiring harnessbms

Related codes

P2BC4P2BCCP2BCDP2BCEP0D0E

References: law.cornell.edu, patents.google.com, patents.google.com.