Powertrain, generic · Hybrid propulsion

P0DAD Hybrid/EV Battery Cell Balancing Circuit A Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0DAD means balancing circuit A keeps draining its cells although the controller has not asked for it: the bleed switch is stuck closed and the resistor keeps pulling those cells down. Ford uses the code in the BECM of its hybrids; the 2019 OBD summary gives each of 14 circuits six cells and, at key-on with the contactors still open, rates a circuit faulty when one of its cells departs from the mean for 0.1 s by over 75 mV. Toshiba's patent US20130026994A1 detects such a shorted balancing switch with a comparator. Left alone, the affected cells sink below the rest, particularly while the car is parked, and the usable pack window shrinks. Which cells form group A is up to the maker.

Likely causes

Balancing transistor of circuit A shorted (fails closed)
Monitoring chip or its drive output keeps the switch enabled
Controller software leaving a balancing request active

Symptoms

  • Hybrid or EV battery warning with the MIL
  • Cells of one group noticeably lower after the car has been parked
  • Range or electric assistance decreasing over days

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 abms

Related codes

P0DABP0DACP0DAEP0DAFP0DB1

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