Powertrain, generic (extended)

P2DB8 Battery Charging System B High Voltage Interlock Circuit Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2DB8 means the interlock loop of charging system B carries a signal, but one that does not behave as the control unit expects. A common test switches the module's test source on and off and checks that the sensed level follows; a reading that stays put or hovers between the valid bands points to contact resistance, a half-seated plug or corrosion rather than a clean break. No manufacturer documents P2DB8 publicly. GM's Volt summary tables (2011, 2014) judge the A-side charging loop in exactly these two states, sourced and unsourced, against separate limits (P0D17, P0D18). The hard open is P2DB7, fixed low or high levels P2DB9 and P2DBA. While the fault is present, path B is normally not used for charging.

Likely causes

Raised contact resistance in an interlock terminal
Plug in the charging path inserted only partway
Corrosion or moisture in an interlock connector
Test source or measuring stage of the module not working correctly

Symptoms

  • Charging via path B refused or interrupted
  • Charging system warning message

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–4 h

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

Parts involved

bcs b hv interlockwiring harnesson board charger

Related codes

P2DB7P2DB9P2DBAP2DBBP0D16

References: gsi.ext.gm.com, gsi.ext.gm.com.