What it means
The voltage of HV battery D is below the expected window. Cell-group depleted, deeply aged, or sense fault.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery control system measures the voltage of hybrid/EV battery D, a monitored section of the high-voltage pack. This code sets when that section's reported voltage falls below its expected range, which can result from aged cells, deep discharge, or an imbalance between battery sections.
Common causes
Most likely first.
- Cells in group aged - capacity reduced
- Deep discharge event
- Pack cell imbalance approaching service threshold
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 compare battery D voltage with neighboring sections and the vehicle's charge state to see when the low reading occurred.
- With the vehicle powered down, inspect accessible battery D sense wiring and connectors for damage, looseness, or corrosion; do not open the high-voltage pack.
- Use a scan tool to monitor battery D and neighboring section voltages during charging and under load, noting whether D remains low or recovers.
- Check the battery D sense circuit and its connections for an inaccurate low reading using the manufacturer's procedure.
- If the measurement circuit is sound, have a qualified hybrid technician test battery D for reduced capacity, deep discharge effects, and imbalance.
Common fixes
- Repair loose, damaged, or corroded battery D sense wiring or connector pins.
- Repair a confirmed battery D voltage-sense circuit fault.
- Correct a charging or operating condition that caused deep discharge, if identified by diagnosis.
- Service or replace affected battery modules if testing confirms aged cells or persistent imbalance.
Can I keep driving?
Avoid long trips and heavy acceleration if power is reduced or charging is limited; the vehicle may enter limp mode or lose hybrid assistance. Arrange prompt diagnosis, especially if it will not charge or remain in ready mode, and do not touch high-voltage components.
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.