P0B4C code meaning
Hybrid/EV Battery Voltage Sense D Circuit Low
Powertrain system Generic code P0Bxx codes Check engine light
What P0B4C means
From the driver's seat P0B4C looks like a battery problem: the hybrid warning comes on and electric power is cut back. Technically it is a measuring fault on cell channel D, whose reading has fallen below what even a deeply discharged cell would show. GM's battery energy control module uses 0.2 V or less, held for 1.4 s within 2 s, Type A, and skips the test while open sense line or communication faults are active. On the 2012 two-mode full-size hybrids, channel D is block 4, and the code needs blocks 4 and 5 both below 2 V in 15 of 20 samples, Type B. A genuinely weak cell produces separate cell voltage codes, so P0B4C points to wiring or the monitoring module.
P0B4C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.3 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B4C
- Hybrid warning message and MIL
- Electric power and regeneration cut back
- Engine runs more often than usual
Common causes of P0B4C
- Most likelyShort between channel D sense line and a neighbouring line
- PossibleDefective input on the cell monitoring module
- Less likelyCorroded tap shared by blocks 4 and 5 (GM two-mode)
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 dWiring harnessBms
What each part of P0B4C 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. |
| 4C | The exact fault in that area. |
What to do next
- Note P0B4C 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 P0B4C
What does P0B4C mean?
P0B4C means "Hybrid/EV Battery Voltage Sense D Circuit Low". From the driver's seat P0B4C looks like a battery problem: the hybrid warning comes on and electric power is cut back. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B4C?
Drive gently and only to a workshop. With P0B4C the car can go into limp mode (reduced power) to protect itself.
Will P0B4C fail an emissions test?
Yes, it can. P0B4C 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 P0B4C to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 6 hours of work. This is a job for a workshop.
Will P0B4C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.