P0B7A code meaning
Hybrid/EV Battery Voltage Sense M Circuit High
Powertrain system Generic code P0Bxx codes Check engine light
What P0B7A means
A reading on channel M above what any healthy cell can deliver produces P0B7A. For lithium-ion packs GM sets the line at 4.8 V or more for 1.4 s in a 2 s window and treats it as Type A, illuminating the MIL on the first trip. The BAS Plus mild hybrid already reacts above 4.65 V in 7 of 10 samples, Type B. Where M stands for NiMH block 13, as on the 2012 two-mode trucks, a block voltage above 23 V for 15 of 20 samples is the trigger, again Type B, with the 12 V system between 9 and 18 V. Because a cell itself rarely climbs that high, a sense lead touching a higher potential or a faulty measuring input is far more likely than overcharging. The vehicle will usually limit charging and electric drive.
P0B7A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0B7A
- MIL on from the first trip (GM lithium-ion, Type A)
- Charging stopped or limited
- Reduced electric power
Common causes of P0B7A
- Most likelySense lead M in contact with a higher cell potential
- PossibleMeasuring input of channel M reading high
- Less likelyReal overvoltage of the cell after a balancing fault
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 mWiring harnessBms
What each part of P0B7A 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. |
| 7A | The exact fault in that area. |
What to do next
- Note P0B7A 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 P0B7A
What does P0B7A mean?
P0B7A means "Hybrid/EV Battery Voltage Sense M Circuit High". A reading on channel M above what any healthy cell can deliver produces P0B7A. It is a generic code, so it means the same on every make.
Is it safe to drive with P0B7A?
Drive gently and only to a workshop. With P0B7A the car can go into limp mode (reduced power) to protect itself.
Will P0B7A fail an emissions test?
Yes, it can. P0B7A 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 P0B7A to fix?
Difficulty: workshop only. A typical repair takes 1 to 8 hours of work. This is a job for a workshop.
Will P0B7A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.