What it means
The signals of the HV battery temperature sensors B and C do not correlate within the calibrated tolerance.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The HV battery control system checks whether temperature sensors B and C report a plausible relationship. This code sets when their readings differ beyond the calibrated tolerance, potentially making the battery’s temperature picture unreliable.
Common causes
Most likely first.
- Faulty battery temperature sensor B or C
- Damaged wiring or poor connection in a sensor circuit
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
- Use a hybrid-capable scan tool to capture freeze-frame data and compare live readings from sensors B and C with the other pack sensors.
- With the vehicle safely powered down, inspect the sensor B and C connectors and harness sections for poor seating, corrosion, pin damage, or abrasion.
- Look for a B or C reading that is stuck, jumps intermittently, or conflicts with pack and ambient temperature conditions.
- Using the vehicle wiring diagram, test the B and C sensor circuits for opens, shorts, and poor connections according to the manufacturer's procedure.
- If the circuits are sound, test sensors B and C individually to the manufacturer's specification and replace only the sensor that fails.
Common fixes
- Reseat or repair a loose or damaged sensor B or C connector.
- Repair damaged wiring in the B or C temperature-sensor circuit.
- Replace sensor B or C if its individual test is out of specification.
- Clear the code and verify B and C readings remain plausible through the manufacturer's check.
Can I keep driving?
Limit driving and charging until the B/C temperature mismatch is diagnosed, because the vehicle may reduce power or restrict charging to protect the HV battery. Stop safely if power drops sharply or a hybrid warning escalates.
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.