Powertrain, generic · Hybrid propulsion

P0BAC Hybrid/EV Battery Voltage Sense W Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BAC is the upper counterpart to P0BAB: channel W reports more voltage than a single cell can plausibly hold. GM sets the limit at 4.8 V or more for 1.4 s within 2 s in the 2011 and 2016 Volt battery modules, which makes it a one-trip fault. The 16OBDG02 programme fails at above 4.90 V in 14 of 18 samples, Type A, while the eAssist battery is stricter with more than 4.65 V in seven of ten samples, Type B. A high reading usually comes from a lead touching the potential of the next cell up or from a faulty input, less often from a genuinely overcharged cell. Because overcharging is a safety risk, the controller typically cuts charging and regeneration until the cause is found.

Likely causes

Sense lead W in contact with a higher cell potential
Monitoring board input for W reading too high
Cell W actually overcharged after a balancing fault

Symptoms

  • MIL and battery system warning
  • Charging and regeneration stopped
  • Possible reduced power mode

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–6,000
Time1–8 h

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

Parts involved

hv battery voltage sense wwiring harnessbms

Related codes

P0BA9P0BAAP0BABP0BADP0BA7P0BB1

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