What it means
The hybrid control module detects that the power electronics coolant pump A is running above the calibrated maximum speed without load. Indicates dry running due to coolant loss or air ingestion.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Power-electronics coolant pump A circulates coolant through the inverter and related electronics cooling loop. The hybrid control module monitors its speed and load; this code sets when pump A exceeds its calibrated speed limit while apparently unloaded, commonly because coolant is missing or air has entered the loop.
Common causes
Most likely first.
- Coolant loss in electronics loop
- Air drawn into pump suction
Symptoms
- Hybrid-system or powertrain warning light
- Reduced hybrid or electric drive power
- Power-electronics overheating warning
How to diagnose it
- Review freeze-frame and live data for pump A command and speed, power-electronics temperature, and related cooling faults.
- Check the electronics-loop coolant level and look for visible leaks, following the manufacturer's high-voltage safety procedures.
- Inspect pump A's accessible hoses and connections for looseness, air entry, kinks, or leakage.
- Inspect pump A's connector and harness, then compare commanded and reported speed using scan-tool data.
- If the loop is full and sealed but overspeed remains, check for trapped air and test pump A using the manufacturer's procedure.
Common fixes
- Repair leaks or loose connections in the power-electronics cooling loop.
- Refill and bleed the electronics loop according to the manufacturer's procedure.
- Repair pump A connector or wiring faults affecting its speed signal.
- Replace pump A if it still overspeeds without load after the loop is corrected.
Can I keep driving?
Power-electronics cooling may be inadequate, so the vehicle can reduce drive power and the electronics may overheat. Avoid hard acceleration and stop safely if an overheating 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.