What it means
The signals of the HV battery temperature sensors A and B 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 compares temperature readings from battery sensors A and B for a plausible relationship. This code sets when those two readings differ beyond the vehicle’s calibrated tolerance, which can make battery temperature monitoring less reliable.
Common causes
Most likely first.
- Faulty battery temperature sensor A or B
- 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 record freeze-frame data and compare live readings from sensors A and B, noting whether the mismatch occurs when the pack should be at a uniform temperature.
- With the vehicle safely powered down, inspect the accessible sensor A and B harnesses and connectors for looseness, corrosion, pin damage, or chafing.
- Check whether either sensor reading is fixed, erratic, or implausible compared with the other battery temperature readings and ambient conditions.
- Test the A and B sensor circuits for continuity, shorts, and connection quality using the vehicle wiring diagram and manufacturer's procedure.
- If the wiring checks pass, test the sensors individually to the manufacturer's specification and replace the sensor shown to be faulty.
Common fixes
- Reconnect or repair a loose or damaged sensor A or B connector.
- Repair chafed, corroded, or open wiring in the affected sensor circuit.
- Replace the faulty battery temperature sensor A or B after circuit testing identifies it.
- Clear the code and confirm sensors A and B track plausibly during the manufacturer's verification procedure.
Can I keep driving?
Avoid relying on electric power or charging until the battery temperature readings are checked; the vehicle may limit power or refuse charging to protect the HV battery. If power is reduced or another hybrid warning appears, stop somewhere safe and arrange service.
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.