Powertrain, generic · Hybrid propulsion

P0BA2 Hybrid/EV Battery Voltage Sense U Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BA2 flags an excessive voltage on channel U. GM's eAssist mild hybrid uses the lowest threshold of the documented systems: above 4.65 V in 7 of 10 samples with the 12 V supply above 8.8 V, Type B. The 2016 Volt and the 2019 battery controller set it at 4.8 V or more held for 1.4 s within 2 s, Type A; the 16OBDG02 programme at above 4.90 V in 14 of 18 samples, Type A. As with the low code, the high test is held back while an open sense line or module communication fault is active. Channel U does not exist on the twenty-block two-mode trucks. Before replacing parts, the actual cell voltage should be measured, because a lead touching a higher potential is far more common than a real overcharge.

Likely causes

Sense lead U in contact with a higher potential
Measuring IC misreading channel U
Cell U actually overcharged

Symptoms

  • MIL and hybrid or EV warning
  • Charging stopped early

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

P0B9FP0BA0P0BA1P0BA3P0B9DP0BA7

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