What it means
The control module detects a range or performance fault in the hybrid/EV battery pack voltage sense B circuit.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery pack voltage sense B circuit provides a voltage reading that the control module uses to monitor the hybrid or EV battery. P0B15 sets when the sense B reading is outside the expected range or does not respond as expected, even if the circuit is not simply registering a low or high signal.
Common causes
Most likely first.
- Voltage sense signal outside expected range
- Sensing circuit or connection 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 monitor live voltage sense B readings to see whether they are out of range, unstable, or inconsistent with other battery voltage data.
- With the vehicle powered down as specified by the manufacturer, inspect the sense B wiring and connector for damage, corrosion, loose terminals, or poor contact.
- Check for related battery voltage sensing or reference codes that could explain an abnormal reading.
- Using the wiring diagram, test the sense B signal path and its connections for faults, comparing results with the manufacturer's specification.
- Compare sense B operation with other available battery voltage readings under the specified conditions to distinguish a sensor response problem from a wiring or connection fault.
Common fixes
- Reseat the sense B connector and repair loose or corroded terminals.
- Repair damaged wiring or a poor connection in the voltage sense B circuit.
- Restore the circuit's reference or ground connection to the manufacturer's specification.
- Replace the sensing component if its response remains out of range after the circuit is verified.
Can I keep driving?
Limit driving if the vehicle is in reduced-power mode or charging is affected, and avoid relying on electric range. Continued operation with an implausible battery voltage reading can lead the system to restrict battery use or charging.
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.