What it means
The HV battery pack coolant pump A is mechanically stuck or has stalled. Battery thermal management severely impaired.
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 coolant pump circulates coolant to control pack temperature. This code indicates that the battery control system detects the pump stalled or unable to turn, so battery cooling can be seriously reduced and power or charging may be limited.
Common causes
Most likely first.
- Pump impeller jammed
- Motor seized
- 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
- Read freeze-frame data and battery live data for temperature, pump command, and any related thermal-management faults.
- Check the coolant level and inspect the pump and accessible coolant lines for leaks, blockage, or signs of damage, following high-voltage safety guidance.
- Use the manufacturer’s scan-tool procedure to compare the commanded pump operation with its reported speed or status.
- Have the pump circuit, connector, and supply checked using the manufacturer’s high-voltage isolation and test procedure.
- If the pump circuit is sound, investigate the pump for a seized motor or jammed impeller and assess battery temperature and cell data for related problems.
Common fixes
- Correct a coolant leak or restriction identified in the battery cooling circuit.
- Repair a damaged pump connector or wiring fault.
- Replace the coolant pump if it is confirmed stalled or mechanically seized.
- Address battery cell imbalance or pack faults if the manufacturer’s diagnostic results identify them.
Can I keep driving?
Avoid driving or charging if the vehicle shows a battery temperature, hybrid/EV system, or reduced-power warning; continued use can overheat and damage the battery. If the warning is active, stop in a safe place and follow the vehicle’s instructions.
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.