Powertrain, generic · Hybrid propulsion

P0B27 Hybrid/EV Battery B Voltage

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B27 is the general voltage fault of hybrid/EV battery B, the second separately monitored sub-battery or energy store. It covers a voltage that does not match expectation without saying whether it is unstable (P0B28), too low (P0B29) or too high (P0B2A). That battery B exists in production systems is shown by Stellantis, whose Jeep Wrangler 4xe bulletin lists P0B28; P0B27 itself is not documented publicly by any manufacturer. GM's analogous monitors of the whole pack are P0ABB to P0ABD, for example a pack reading more than 12 V away from the sum of the cells. CARB requires the voltage sensors and cells of hybrid storage systems to be monitored. The driver gets a hybrid warning and reduced battery power.

Likely causes

Weak or failing cells or module in battery B
Fault in the voltage sense leads or connectors of battery B
Battery controller software or internal measurement fault

Symptoms

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

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

P0B28P0B29P0B2AP0B23P0B2BP0B2FP0ABB

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