P0B99Hybrid/EV Battery Voltage Sense S Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B99 is the erratic variant within the sense S group. A public manufacturer description does not exist. GM's tables cover channel S from the 2011 Volt via the 2012 two-mode trucks and eAssist to the 2019 controllers, yet only with circuit, range, low and high codes (P0B95 to P0B98). CARB 1968.2 obliges manufacturers to monitor battery voltage sensors of a hybrid storage system for circuit and rationality faults and to separate the fault codes by replaceable unit, which is why J2012 reserves this slot. Should a vehicle set it, the technician would look for a sense S connection that works most of the time but breaks briefly, typically a fretting terminal or a cracked solder joint on the board.
- What you may notice
- Sporadic hybrid warning without a pattern
- Code often stored as history, hard to reproduce
- Likely causes
- LikelyFretting corrosion on the terminal of sense lead S
- PossibleCracked solder joint for channel S on the monitoring board
- RareHarness chafing that only shorts under movement
- 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: €80 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.