Powertrain, generic · Hybrid propulsion

P0B30 Hybrid/EV Battery D Voltage Unstable

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B30 reports an unstable voltage of hybrid/EV battery D: the measured value fluctuates beyond the limit the controller allows. It differs from P0B31 and P0B32, which stand for a lasting low or high voltage, and from the general fault P0B2F. No manufacturer documents P0B30 publicly. The sibling codes for batteries A and B show the typical background: Stellantis and Ford corrected P0B24 and P0B28 by updating the battery controller software, and Jeep even blocks starting after 49 days with P0B28. CARB requires the hybrid storage voltage sensors to be monitored. Apart from software, poor contact at busbars or sense terminals and cells with high internal resistance make the reading of unit D jump.

Likely causes

Loose busbar, terminal or sense contact in battery D
Battery controller software (pattern known from P0B24/P0B28)
Cell with rising internal resistance in battery D

Symptoms

  • Hybrid/EV system or high-voltage battery warning on
  • MIL on
  • Warning comes and goes, fault often stored as intermittent
  • Battery power limited, less electric drive or assist

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–3,000
Time0.5–8 h

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

Parts involved

hv battery dbms

Related codes

P0B2FP0B31P0B32P0B24P0B28P0B2C

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.