P0B3B code meaning
Hybrid/EV Battery Voltage Sense A Circuit
Powertrain system Generic code P0Bxx codes Check engine light
What P0B3B means
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.
P0B3B 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 P0B3B
- 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
Common causes of P0B3B
- Most likelyOpen cell sense line, splice or bus bar connection inside the pack
- PossibleIntermittent fault in the flexible printed circuit to the battery controller (Ford Mach-E)
- PossibleSensor software misreading inverter noise, fixed by update (Honda)
- Less likelyInternal failure of the traction battery 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 aWiring harnessBms
What each part of P0B3B 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. |
| 3B | The exact fault in that area. |
What to do next
- Note P0B3B 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 P0B3B
What does P0B3B mean?
P0B3B means "Hybrid/EV Battery Voltage Sense A Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B3B?
Drive gently and only to a workshop. With P0B3B the car can go into limp mode (reduced power) to protect itself.
Will P0B3B fail an emissions test?
Yes, it can. P0B3B 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 P0B3B to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 8 hours of work. This is a job for a workshop.
Will P0B3B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.