Powertrain, generic (extended)

P2D63 Battery Charging System Negative Contactor C Stuck Closed

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P2D63 says negative charging contactor C has not opened on command; the return-side contacts are almost certainly fused. No manufacturer documents P2D63 publicly, and the Mercedes and Mazda bulletins that report a welded minus contactor B (P2BCC) do not mention C. Detection relies on isolating one pole at a time: Toyota opens the minus charge relay while the plus relay stays closed and treats it as stuck if the charging inlet voltage stays above a threshold; it repeats the test with the main relays open to exclude a charger that keeps supplying power. Hyundai uses the same pairing at the end of quick charging. With a welded minus pole the inlet is no longer isolated on that side, so the module blocks the path. P2D64 is the opposite fault, P2D5C the plus side.

Likely causes

Fused main contacts of minus contactor C
Charger still supplying voltage during the check (false detection)
Coil output stage stuck on

Symptoms

  • Charging blocked after a session
  • High-voltage warning at start-up
  • Vehicle may not become ready if the plus side is welded too

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€200–4,000
Time1–10 h

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

Parts involved

bcs neg contactor cwiring harnessbms

Related codes

P2D62P2D64P2D5CP2BCCP0D0F

References: patents.google.com, patents.google.com, patents.google.com.