What it means
The BMS detects a circuit low fault on voltage sense channel N of the high-voltage battery. Cell-group voltage measurement is unreliable on this channel.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery management system reads the voltage of a cell group through battery sense channel N. P0B7E sets when that channel's signal falls below the module's expected range, so the reported voltage for that group cannot be trusted.
Common causes
Most likely first.
- Sense wire shorted to ground
- Open in sense wire
- Connector pins corroded - high contact resistance
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Save freeze-frame data and compare channel N's live voltage with adjacent cell-group readings to confirm the low signal and note when it occurs.
- Check whether charging or power limitation is present, since the BMS may restrict operation when channel N cannot be monitored reliably.
- With the high-voltage battery safely isolated according to the vehicle's service procedure, inspect channel N's accessible wiring and connectors for damage, corrosion, or moisture.
- Have a qualified hybrid technician test the channel N sense wire for a short to ground, an open, or excessive resistance against the manufacturer's procedure.
- If the wiring and contacts pass, compare the battery monitoring module's channel N input with the measured group voltage to identify a module-side fault.
Common fixes
- Repair damaged channel N sense-wire insulation or wiring that is shorted to ground.
- Restore continuity in an open channel N sense wire.
- Clean or repair corroded channel N connector terminals and ensure a sound connection.
- Replace or repair the battery monitoring module if its channel N input is faulty after wiring checks.
Can I keep driving?
Avoid relying on electric propulsion or attempting long trips; reduced power or a charging restriction may leave the vehicle unable to perform as expected. If the warning is accompanied by severe power loss or other high-voltage battery warnings, stop in a safe place and arrange qualified hybrid service.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.