Powertrain, generic · Hybrid propulsion

P0B45 Hybrid/EV Battery Voltage Sense C Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Voltage sense C is the third cell or cell-group measuring channel of the battery monitoring electronics, not a pack voltage input like P0ABA. P0B45 reports an electrical break in that channel. GM's battery energy control module sets it when its open sense line test fails for 0.6 s: adjacent cell readings at least 1.3 V apart, a cell below 36 mV while its balancing switch is on, or a splice above 0.1 V (bus bar splice 0.5 V); Type A, one trip. Ford lists P0B45 with the other open-line codes on the 2019-2020 Fusion plug-in hybrid, fixed by a new traction battery, and on the 2023 Mustang Mach-E and E-Transit, where an intermittent BECM flexible printed circuit is blamed. Expect no start or no charging.

Likely causes

Open cell sense tap, splice or bus bar connection on channel C
Intermittent flexible printed circuit between cells and battery controller (Ford Mach-E, E-Transit)
Internal traction battery failure requiring pack replacement (Ford Fusion PHEV)

Symptoms

  • Vehicle does not start or does not become ready to drive
  • High-voltage battery no longer charges
  • Powertrain warning (wrench) and Stop Safely Now message

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 cwiring harnessbms

Related codes

P0B46P0B47P0B48P0B49P0B40P0B4A

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