What it means
The control module detects a range or performance fault in the hybrid/EV battery pack voltage sense C circuit.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery management module reads pack-voltage sense channel C to track the voltage represented by that part of the hybrid or EV battery pack. It sets P0B1A when the C-channel reading is outside the expected range or does not behave as expected, without specifying whether the signal is low, high, or erratic.
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 read battery-management live data for voltage sense C alongside other pack-sense channels to see when and how its reading diverges.
- Check for related battery or sensing codes, which can help distinguish a channel C fault from a broader pack or module problem.
- Visually inspect the channel C sensing connector and accessible wiring for looseness, corrosion, damage, or signs of overheating.
- With the manufacturer's service information, compare the channel C signal and relevant connections with the specified values and the other sense channels.
- If the wiring and connections check out, have the battery monitoring hardware and pack diagnosed using the vehicle's high-voltage safety procedures.
Common fixes
- Reseat a loose channel C sensing connector using the manufacturer's procedure.
- Repair damaged or corroded channel C wiring or terminals.
- Restore a faulty sensing-circuit connection or ground reference.
- Replace a confirmed faulty voltage-sensing component or battery monitoring module.
Can I keep driving?
Because the fault can trigger reduced power, limp mode, or charging problems, avoid long trips and situations that require dependable acceleration. Stop safely if power drops sharply or the vehicle displays a high-voltage battery warning.
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.