Powertrain, generic · Hybrid propulsion

P0B59 Hybrid/EV Battery Voltage Sense G Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Voltage sense G is the seventh cell measuring channel; how many cells or groups it covers depends on how the manufacturer splits the pack among monitoring chips. P0B59 is its open-circuit code. Two Ford bulletins name it: the 2019-2020 Fusion PHEV, where the open-line group up to P0B7C leads to a battery replacement, and the 2023 Mach-E and E-Transit, where it is blamed on the BECM flexible printed circuit. GM's BECM sets it after 0.6 s of an open-line pattern such as adjacent cells 1.3 V apart, a balanced cell under 36 mV or splice voltages above 0.1 V or 0.5 V, Type A. If several channels report at once, suspect a shared connection first.

Likely causes

Open channel G tap, splice or bus bar contact
Intermittent BECM flexible circuit (Ford Mach-E, E-Transit)
Internal traction battery failure (Ford Fusion PHEV)

Symptoms

  • Vehicle not ready to drive
  • Charging blocked
  • Wrench light or hybrid warning

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 gwiring harnessbms

Related codes

P0B5AP0B5BP0B5CP0B5DP0B54P0B5E

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