Powertrain, generic · Hybrid propulsion

P0BA0 Hybrid/EV Battery Voltage Sense U Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BA0 tells the technician that channel U gives a number, but the number does not move with the pack. GM checks this rationality only on lithium-ion systems, since the two-mode NiMH trucks end at block 20. The Cadillac ELR of 2016 reacts to the smallest movement: when the average cell voltage changes by more than 0.006 V, cell U must follow, and 20 failures in 40 samples at 200 ms set a Type A fault. The Volt of the same year looks at 0.022 V of average movement and a 7 s in 8 s window, the 2019 hybrid processor at 0.005 V with 35 of 40 samples, and eAssist at half the average movement, Type B. Circuit, low and high faults are excluded before the test runs, so wiring is less likely than the controller.

Likely causes

Measuring channel U holding a fixed value
Software or calibration issue in the battery controller
Cell U behaving differently from its neighbours due to ageing

Symptoms

  • MIL, often without driver-noticeable change
  • Electric range may be reduced

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–5,000
Time0.5–6 h

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

Parts involved

hv battery voltage sense uwiring harnessbms

Related codes

P0B9FP0BA1P0BA2P0BA3P0B9BP0BA5

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