Powertrain, generic · Hybrid propulsion

P0BA1 Hybrid/EV Battery Voltage Sense U Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BA1 is stored when sense U reads close to zero. GM's lithium-ion controllers of the 2016 Volt and ELR and of 2019 treat 0.2 V or less over 1.4 s in a 2 s window as a Type A fault, provided no open sense line, lost slave communication or balancing fault is already active. The 16OBDG02 programme with its own battery sensor module uses under 0.20 V in 14 of 18 samples. GM's eAssist mild hybrid applies a much higher limit of 1.4 V in 7 of 10 samples, Type B. The two-mode NiMH trucks have no channel U. A short in the sense lead or a failed measuring input is the most likely finding.

Likely causes

Sense lead U shorted towards ground or a lower cell
Dead measuring input for channel U
Cell U internally shorted or deeply discharged

Symptoms

  • MIL and EV or hybrid system warning
  • Propulsion power limited

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 uwiring harnessbms

Related codes

P0B9FP0BA0P0BA2P0BA3P0B9CP0BA6

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