What it means
The hybrid control module detects that battery pack coolant pump A does not produce the expected flow for the commanded duty. Battery thermal management may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery pack coolant pump A circulates coolant through the battery thermal-management loop. The hybrid control module compares the pump's commanded operation with its performance and sets this code when pump A does not produce the expected flow; battery temperature control and charging may be affected.
Common causes
Most likely first.
- Pump output degraded with age
- Air pocket in coolant loop
- 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
- Check freeze-frame data and hybrid-system live data for pump A command, reported speed or flow, battery temperatures, and any related cooling codes.
- Inspect the battery cooling loop's visible coolant level and accessible hoses for leaks, kinks, or signs of air entry, following the manufacturer's high-voltage safety procedures.
- Inspect pump A's connector, wiring, and accessible coolant connections for damage, corrosion, looseness, or leakage.
- Use scan-tool controls and service information to compare pump A's commanded operation with its reported operation and check whether flow responds.
- If command and electrical supply are present but performance remains low, check the loop for air or restriction and test pump A against the manufacturer's specification.
Common fixes
- Repair a loose or corroded pump A electrical connection.
- Repair coolant leaks or restrictions in the battery cooling loop and refill or bleed it by the manufacturer's procedure.
- Replace pump A if it cannot produce the specified performance.
- Address battery-pack imbalance only if separate diagnostic results confirm it requires service.
Can I keep driving?
Reduced power, slower or unavailable charging, and reduced electric range can follow as battery temperatures become harder to control. Avoid fast charging and high-load driving; stop if a battery or cooling warning appears.
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.