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.
High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
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
Most 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)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P0B45 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- B: Subsystem depends on the code range
- 45: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0B45?
If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
What causes code P0B45?
The most common causes are: 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).
Related codes
- P0B46Hybrid/EV Battery Voltage Sense C Circuit Range/Performance
- P0B47Hybrid/EV Battery Voltage Sense C Circuit Low
- P0B48Hybrid/EV Battery Voltage Sense C Circuit High
- P0B49Hybrid/EV Battery Voltage Sense C Circuit Intermittent/Erratic
- P0B40Hybrid/EV Battery Voltage Sense B Circuit
- P0B4AHybrid/EV Battery Voltage Sense D Circuit
Sources
- gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
- static.nhtsa.gov: MC 10232489 0001
- static.nhtsa.gov: MC 11005840 0001
- law.cornell.edu: 13 CCR 1968.2
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.