Powertrain, generic · Hybrid propulsion

P0D25 Battery Charger System Precharge Time Too Short

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0D25 is about the precharge of the charger's high-voltage bus, the short phase before the charging contactors close in which the bus capacitance is brought up to battery voltage through a limiting path. The code means this voltage arrived sooner than physically plausible. No manufacturer documents P0D25 publicly. GM describes the counterpart test for the charger bus under P0D26, with a window of 5 % around pack voltage, and the same principle for the main battery under P0C77, where the 2011 Volt flags a rise above 95 % within 50 ms. A rise that quick suggests a bypassed precharge resistor, a contactor that is welded or closes early, missing bus capacitance or a voltage sensor reporting wrong values. CARB requires charger faults that affect charging to be detected. Charging is normally refused.

Likely causes

Precharge resistor bypassed or shorted
Charging contactor welded or closing too early
Bus or pack voltage sensor reporting wrong values
Bus capacitance much lower than expected

Symptoms

  • Charging refused at the start of a session
  • Charging system warning

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–2,500
Time1–5 h

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

Parts involved

battery charger precharge circuit

Related codes

P0D26P0C77P0D23

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