What it means
The cell thickness sensor circuit for hybrid/EV battery pack B has a signal below the expected range. This indicates a circuit or sensor signal fault; it does not by itself indicate a cell voltage problem.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The BMS monitors the cell thickness sensor signal circuit in hybrid/EV battery pack B. This code sets when the signal is below its expected range, commonly from a short to ground, a shorted sensor, or poor connector contact; it is not a low cell-voltage code.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- 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
- Record freeze-frame data and view pack B thickness sensor live data to confirm the low signal and whether it is constant.
- Check for related pack B sensor codes and compare other available pack measurements to see whether the fault is confined to this circuit.
- With the vehicle made safe according to the manufacturer's procedure, inspect pack B sensor wiring for a short to ground and examine connectors for corrosion or damaged pins.
- Test the pack B sensor circuit for shorts to ground and check continuity using the manufacturer's wiring information.
- Measure the sensor output against the manufacturer's specifications to distinguish an internally shorted sensor from a harness fault.
Common fixes
- Clean and secure corroded or loose pack B sensor connector pins.
- Repair pack B thickness sensor wiring shorted to ground or otherwise damaged.
- Replace the pack B thickness sensor if its output remains below range.
- Verify BMS readings after repair and perform any required manufacturer-specified calibration.
Can I keep driving?
The BMS may reduce power or restrict charging because pack B thickness data is unreliable. Avoid hard acceleration and unnecessary trips; stop using the vehicle if a battery warning worsens, power falls sharply, or the pack becomes unusually hot.
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.