Powertrain, generic · Hybrid propulsion

P0DB1 Hybrid/EV Battery Cell Balancing Circuit B Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0DB1: in circuit B the bleed path stays closed even after the controller withdrew the command. The cells of group B are drained without pause, so their voltage falls behind the others, worst during long standstill. Detection usually compares commanded and reported switch state; GM's eAssist logic for a related code needs 7 failed of 10 samples before a Type B entry. Toshiba describes a comparator check that spots a shorted balancing switch while it should be off. Ford names P0DB1 for its hybrid BECM; the 2015 OBD summary flags it when, at start-up with open contactors, one of the six cells served by circuit B differs from the pack mean by more than 75 mV. The electrical fault of the same circuit is P0DB0, the opposite stuck state P0DB2.

Likely causes

Shorted balancing transistor in circuit B
Drive output of the monitoring chip stuck active
Moisture or contamination on the module board creating a leakage path

Symptoms

  • MIL with battery warning
  • Group B cells clearly low after parking
  • Usable charge and range shrinking

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–4,000
Time2–8 h

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

Parts involved

hv battery cell balancing circuit bbms

Related codes

P0DABP0DB0P0DB2P0DB3P0DAD

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