P0B8C code meaning
Hybrid/EV Battery Voltage Sense Q Circuit Range/Performance
Powertrain system Generic code P0Bxx codes Check engine light
What P0B8C means
P0B8C is set when channel Q reports a voltage that fails the plausibility test against the other cells or the pack. On GM's 2012 two-mode trucks Q is NiMH block 17; the battery pack control module takes block 17 and block 18, multiplies each by twenty and compares with the measured pack voltage, failing beyond 70 V in 160 of 170 samples, Type B. GM's lithium-ion programs instead check that cell Q follows the average: the 2016 Volt within 7 of 8 seconds, the Cadillac ELR in 20 of 40 samples, the 2019 controllers in 35 of 40 samples with a 0.005 V trend, all Type A. Because the value itself is within limits, the driver may notice little beyond the MIL. A software update or replacement of the monitoring electronics resolves most cases.
P0B8C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B8C
- MIL with little change in driving
- Usable battery capacity reduced
Common causes of P0B8C
- Most likelyMonitoring electronics misreading channel Q
- PossibleOutdated battery controller software
- Less likelyBlock 17 or 18 voltage deviating on two-mode NiMH packs
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 qWiring harnessBms
What each part of P0B8C 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. |
| 8C | The exact fault in that area. |
What to do next
- Note P0B8C 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 P0B8C
What does P0B8C mean?
P0B8C means "Hybrid/EV Battery Voltage Sense Q Circuit Range/Performance". P0B8C is set when channel Q reports a voltage that fails the plausibility test against the other cells or the pack. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B8C?
Drive gently and only to a workshop. With P0B8C the car can go into limp mode (reduced power) to protect itself.
Will P0B8C fail an emissions test?
Yes, it can. P0B8C 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 P0B8C to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 6 hours of work. This is a job for a workshop.
Will P0B8C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.