What it means
The high-voltage system voltage does not match plausibility checks under load. Voltage trace deviates from expected battery profile.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The high-voltage battery supplies electric drive and hybrid functions, and the battery management system tracks how pack voltage changes with operating load. This code sets when the voltage response fails the system's plausibility checks, even if it is not simply too low or too high.
Common causes
Most likely first.
- HV battery cells aged
- BMS regulation outside calibration
Symptoms
- Check-engine or hybrid-system warning light may be on
- Reduced power or limited vehicle operation
- Electric driving range or hybrid assist may be reduced
How to diagnose it
- Review freeze-frame data and hybrid-system codes to identify the load and operating conditions when the voltage trace failed its plausibility check.
- Use a compatible scan tool to compare pack and battery-section voltage changes during the recorded conditions, following the manufacturer's diagnostic procedure.
- Check for related battery-temperature, current-sensing, charging, or isolation faults that could make the voltage response appear implausible.
- Have the high-voltage battery connections and pack condition checked with the manufacturer's safety procedures; do not probe high-voltage components yourself.
- If the battery and connections pass inspection, evaluate battery-management system sensing and regulation against the manufacturer's specification.
Common fixes
- Repair a confirmed battery connection or sensing fault affecting the voltage profile.
- Address a related temperature or current-sensing fault if diagnostics show it is distorting battery data.
- Replace a battery module or pack only if testing confirms its voltage response is abnormal.
- Repair or update battery-management system control as directed by manufacturer diagnostics.
Can I keep driving?
Limit hard acceleration and avoid relying on full electric range or hybrid assist because the vehicle may reduce power or enter limited operation. If a high-voltage warning appears or power becomes unpredictable, stop safely and arrange assessment by a qualified hybrid technician.
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.