Powertrain, generic (extended)

P2D5B Battery Charging System Positive Contactor C Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2D5B is the umbrella electrical fault for charging-system contactor C on the plus pole, a third plus-side switch next to contactors A (P0D07) and B (P2BC4). Which charging path C serves is left to each maker, and none states it in public: the bulletins that cite contactor B codes (Mercedes, Mazda, Audi) never mention a C contactor, nor do the published GM tables, and no document lists P2D5B itself. CARB obliges plug-in hybrids to catch charger faults that stop or curb charging. One GM patent assesses this kind of contactor from its coil current after a brief test pulse. Welding and failure to close have their own codes (P2D5C/P2D5D), coil-drive faults P2D5E–P2D61. Expect the charging mode behind C to be unavailable.

Likely causes

Coil of contactor C open or shorted internally
Damaged wiring or loose plug at the contactor or its module
Output stage or software of the controlling module

Symptoms

  • One charging mode refused or aborted
  • Charging or high-voltage warning in the cluster
  • Driving otherwise normal

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 pos contactor cwiring harnessbms

Related codes

P2D5CP2D5DP2D5EP2D62P2BC4P0D07

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