What it means
The HV battery pack coolant pump A reports a control performance condition. 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 moves coolant through the battery thermal-management circuit. The module checks whether pump A's operation produces the expected cooling performance; P0C4A sets when performance is inadequate, which can happen with restricted flow, low coolant, or air in the circuit.
Common causes
Most likely first.
- Low coolant or restricted flow
- Faulty coolant pump
- Air in the cooling circuit
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 check battery coolant temperatures and pump A command or status in live data for signs that cooling is not keeping up.
- With the vehicle cold and powered down as specified by the manufacturer, check the battery cooling circuit coolant level and look for visible leaks.
- Inspect accessible hoses and passages for kinks or restrictions that could reduce flow through the battery circuit.
- Use the scan tool's supported pump test, if available, and check for evidence that pump A runs and coolant circulates.
- If coolant level and flow path appear sound, bleed or test the circuit and pump using the manufacturer's procedure to find air or a weak pump.
Common fixes
- Top up with the specified coolant if the level is low, then find and repair any leak.
- Remove an accessible restriction or repair a kinked battery-cooling hose.
- Bleed trapped air from the circuit using the manufacturer's procedure.
- Replace pump A if it cannot provide the specified flow.
Can I keep driving?
Avoid hard driving and charging because battery cooling performance may be insufficient, potentially leading to reduced power or charging limits. Stop if a battery-temperature warning appears or power drops significantly.
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.