P0B18Hybrid/EV Battery Pack Voltage Sense 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
- P0B18 reports that pack voltage measurement B jumps or drops out briefly instead of failing steadily. The controller detects implausibly fast changes or short signal losses that disappear again, so the fault often shows up as a history code. No manufacturer documents P0B18 publicly; GM, for example, monitors only channel A in its published tables (P0ABB to P0ABD). CARB requires battery voltage sensors of the hybrid storage system to be monitored for circuit faults. Steady faults of channel B use P0B14 to P0B17. Typical triggers are loose sense connectors or chafed leads that react to vibration and temperature, so symptoms come and go.
- What you may notice
- Warning appears and disappears, often stored as history
- Battery power limited, reduced electric drive or assist
- Vehicle may not reach Ready or may shut down the high-voltage system
- Likely causes
- LikelyLoose or corroded sense connector
- PossibleSense lead chafed, intermittent contact
- RareBattery controller software misinterprets transients
- 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 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.