Powertrain, generic · Hybrid propulsion

P0B3B Hybrid/EV Battery Voltage Sense A Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Voltage sense A to Z and beyond are the cell or cell-group sense channels of the battery monitoring electronics, unlike the pack voltage sense codes P0ABA and P0B14 ff, which measure the whole pack. P0B3B is the circuit code for channel A. GM uses it in the battery energy control module as an open sense line check: neighbouring cell readings differ by 1.3 V or more, or a cell reads under 36 mV with balancing on, or a splice reads over 0.1 V (bus bar 0.5 V), for 0.6 s; Type A, one trip. Ford stores P0B3B with other open-line codes on the 2019-2020 Fusion PHEV and 2023 Mach-E; Honda's 2014-2015 Accord Hybrid used it for a cell voltage sensor fault caused by inverter noise.

Likely causes

Open cell sense line, splice or bus bar connection inside the pack
Intermittent fault in the flexible printed circuit to the battery controller (Ford Mach-E)
Sensor software misreading inverter noise, fixed by update (Honda)
Internal failure of the traction battery requiring pack replacement (Ford Fusion PHEV)

Symptoms

  • MIL or powertrain warning, Stop Safely Now message possible
  • No start or no charging
  • Fail-safe EV mode with limited speed and sudden loss of power

Repair estimate

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

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

Parts involved

hv battery voltage sense awiring harnessbms

Related codes

P0B3CP0B3DP0B3EP0B3FP0B40P0ABA

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.