What it means
The BMS detects deterioration in HV battery pack section D. Capacity or internal resistance outside service limits.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery management system monitors individual high-voltage battery sections, with section D tracked separately. It assesses section D's capacity, internal resistance, and balance against the system's service limits. P0EE1 sets when section D's measured condition is outside those limits.
Common causes
Most likely first.
- Cells aged - capacity reduced
- Internal resistance increased
- 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
- Save freeze-frame data and retrieve section D capacity, resistance, and cell-balance measurements from the battery management system.
- Compare section D with the other sections under similar charge and load conditions to identify a section-specific weakness.
- Inspect the battery cooling route and accessible section D connectors for damage, poor contact, or restricted airflow while following high-voltage safety steps.
- Check section D temperature and sensing data for implausible values that may point to a sensor or circuit problem.
- Apply the manufacturer's battery evaluation procedure to confirm whether section D is degraded before replacing battery components.
Common fixes
- Restore battery cooling airflow if the section D path is obstructed.
- Repair a damaged or poorly seated section D connector or harness.
- Replace a confirmed faulty battery sensing component.
- Repair or replace the battery section or pack if testing confirms section D degradation.
Can I keep driving?
Reduced power and possible limp operation can affect acceleration, while charging may be limited or fail; avoid demanding routes and long journeys. Stop safely if the vehicle cannot maintain safe traffic speed.
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.