P0B7AHybrid/EV Battery Voltage Sense M Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- MIL on from the first trip (GM lithium-ion, Type A)
- Charging stopped or limited
- Reduced electric power
- Likely causes
- LikelySense lead M in contact with a higher cell potential
- PossibleMeasuring input of channel M reading high
- RareReal overvoltage of the cell after a balancing fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.