P0B7BHybrid/EV Battery Voltage Sense M 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
- P0B7B is reserved for a sense M signal that flickers: short dropouts or jumps while the circuit is otherwise intact. No manufacturer documents this code publicly. GM's tables for channel M contain open, plausibility, low and high tests but no erratic test, and Ford's Fusion bulletin lists only the open-circuit code P0B77. The legal footing is CARB 1968.2, which requires the battery voltage sensors of a hybrid energy storage system to be monitored as electronic components and demands fault codes that point to the smallest replaceable unit. In practice a loose crimp at the M tap, a chafed lead in the sense harness or a cracked solder joint on the monitoring board would cause such a signal. Expect warnings that come and go.
- What you may notice
- Hybrid warning appearing and clearing again
- Brief drops in electric power
- Likely causes
- LikelyLoose crimp or connector at the channel M tap
- PossibleChafed wire in the cell sense harness
- RareCracked solder joint on the monitoring board
- 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.