Powertrain, generic (extended)

P2DBA Battery Charging System B High Voltage Interlock Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2DBA flags an interlock signal of charging system B that reads too high. A loop fed from a test source and measured at its far end shows a raised level when it is shorted to a supply voltage, or, depending on the circuit, when added resistance or a break lets the measuring input float upward. No manufacturer documents P2DBA publicly. GM checks the A-side loop of the Volt in two states (P0D18): with the 5 V source off, a reading above 24 % of reference counts as a fault, with it on, one above 44 %; both are Type A in the 2011 and 2014 tables. Telling a short to voltage from an open therefore needs both states. The low counterpart is P2DB9. Charging through path B stays blocked.

Likely causes

Interlock wire shorted to a supply voltage
Added resistance or partial break in the interlock loop
Faulty measuring input in the control module

Symptoms

  • No charging via path B
  • 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

P2DB7P2DB8P2DB9P2DBBP0D18

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