Powertrain, generic · Hybrid propulsion

P0B2A Hybrid/EV Battery B Voltage High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B2A is stored when the voltage of hybrid/EV battery B rises above its permitted upper limit. It mirrors P0B29 (too low), while P0B28 covers fluctuation and P0B27 the general fault. No manufacturer explains P0B2A publicly; the closest documented case is Bentley's P0B26 for battery A, where a failing 48 V super capacitor reads too high. GM's analogous whole-pack overvoltage monitor is P0ABD (above 479 V, Type A). CARB demands monitoring of battery voltage sensors and cells in hybrid storage systems. Likely causes are a cell group charged too high because balancing fails, or a measuring fault. To protect the cells the controller restricts charging and recuperation and may open the contactors.

Likely causes

Cell group in battery B charged too high, balancing ineffective
Voltage measurement fault in the controller or sense leads
Battery controller software fault

Symptoms

  • Hybrid/EV system or high-voltage battery warning on
  • MIL on
  • Charging or recuperation restricted
  • Battery power limited, less electric drive or assist

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–4,000
Time1–10 h

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

Parts involved

hv battery bbms

Related codes

P0B27P0B28P0B29P0B26P0ABD

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.