P0B12Hybrid/EV Battery Pack Current Sensor B Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P0B12 covers a current sensor B signal that jumps or drops out in a way real current cannot, typically from a loose connector, a chafed signal wire or noise on the sensor ground. No manufacturer documents this exact code publicly. GM monitors its sensor B channel with the range limits P0B10 and P0B11 and compares it with sensor A through P0B13, which fails above a 10 A difference in 400 of 500 samples, Type A; an erratic channel often shows up there first. CARB requires circuit and rationality monitoring for hybrid battery inputs. Because the fault comes and goes, the code may be the only trace, but during dropouts the controller can still cut battery power or light a warning.
- What you may notice
- Intermittent hybrid or EV warning
- Short power reductions during dropouts
- Code stored without lasting symptoms
- Likely causes
- LikelyLoose connector or poor terminal contact at the current sensor
- PossibleChafed signal or ground wire
- RareElectrical noise on the sensor ground
- 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 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.