P0B45 code meaning
Hybrid/EV Battery Voltage Sense C Circuit
Powertrain system Generic code P0Bxx codes Check engine light
What P0B45 means
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.
P0B45 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B45
- 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
Common causes of P0B45
- Most likelyOpen cell sense tap, splice or bus bar connection on channel C
- PossibleIntermittent flexible printed circuit between cells and battery controller (Ford Mach-E, E-Transit)
- PossibleInternal traction battery failure requiring pack replacement (Ford Fusion PHEV)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery voltage sense cWiring harnessBms
What each part of P0B45 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B | Area: hybrid propulsion. |
| 45 | The exact fault in that area. |
What to do next
- Note P0B45 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0B45
What does P0B45 mean?
P0B45 means "Hybrid/EV Battery Voltage Sense C Circuit". Voltage sense C is the third cell or cell-group measuring channel of the battery monitoring electronics, not a pack voltage input like P0ABA. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B45?
Drive gently and only to a workshop. With P0B45 the car can go into limp mode (reduced power) to protect itself.
Will P0B45 fail an emissions test?
Yes, it can. P0B45 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0B45 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 8 hours of work. This is a job for a workshop.
Will P0B45 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.