What it means
The BMS detects a circuit 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 BMS measures a cell group’s voltage using battery voltage sense channel N. P0B7C sets when the channel N circuit has a detected fault, making that group’s voltage measurement unreliable to the battery management system.
Common causes
Most likely first.
- Open or short in the voltage-sense wiring
- Loose, corroded, or damaged connection
- Battery monitoring module fault
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
- Record freeze-frame data and compare live readings for channel N with adjacent channels to see whether N is missing or implausible.
- With the vehicle safely powered down according to the manufacturer’s procedure, inspect the channel N sense harness and connector for loose seating, corrosion, broken wires, or damaged insulation.
- Check channel N connector pins for looseness, corrosion, or damage that could interrupt the reading.
- Have a qualified hybrid technician test channel N wiring for opens and shorts using the manufacturer’s isolation and measurement procedures.
- If the channel N harness and connectors pass, check the battery monitoring module’s channel N input for an internal fault.
Common fixes
- Reseat or clean a loose or corroded channel N connector.
- Repair an open, shorted, or damaged section of channel N sense wiring.
- Repair damaged channel N connector pins or terminals to restore a secure connection.
- Repair or replace the battery monitoring module if tests confirm the fault is at its channel N input.
Can I keep driving?
Avoid long trips and strenuous driving if the vehicle has reduced power or charging problems, as it may limit output when the channel N cell-group voltage cannot be verified. Arrange prompt diagnosis and stop safely if the vehicle’s power becomes unpredictable.
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.