Powertrain, generic · Hybrid propulsion

P0B2D Hybrid/EV Battery C Voltage Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B2D means the voltage of hybrid/EV battery C is too low compared with what the controller expects. High readings of the same unit are P0B2E, fluctuating ones P0B2C. No manufacturer documents P0B2D publicly; the nearest published case is Bentley's P0B25 for battery A, where a 0.5 V spread between highest and lowest cell points to a defective energy store. GM's corresponding whole-pack check is P0ABC (pack below 24 V). CARB requires that cells and voltage sensors of hybrid storage are monitored and that faults identify the smallest replaceable unit. A worn or deeply discharged module in unit C is the most likely reason. The controller lowers discharge power, so acceleration in electric mode suffers and the engine may run more often.

Likely causes

Aged cells with lost capacity in battery C
Deep discharge or self-discharge after standstill
Voltage measurement fault in the controller or sense leads

Symptoms

  • Hybrid/EV system or high-voltage battery warning on
  • MIL on
  • Battery power limited, less electric drive or assist
  • Combustion engine runs more often (hybrid)

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 cbms

Related codes

P0B2BP0B2CP0B2EP0B25P0B29P0ABC

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