What it means
The hybrid electronics coolant pump A reports a control circuit/open condition. Power electronics cooling may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Electronics coolant pump A circulates coolant through the hybrid or EV power electronics cooling loop. P0CE9 sets when the pump A control circuit is open, such as when the control wire, motor winding, or connector connection cannot complete the circuit, potentially interrupting cooling.
Common causes
Most likely first.
- Open in pump control wire
- Open pump motor
- Pin pushed back out of connector body
Symptoms
- Hybrid or EV system warning light on
- Reduced power or limited vehicle operation
- Cooling-system warning may appear
How to diagnose it
- Read freeze-frame data and check scan-tool pump commands and cooling warnings to establish when pump A is expected to run.
- With the vehicle powered down according to the manufacturer's high-voltage safety procedure, identify pump A and inspect its connector for a pushed-back pin, corrosion, or poor seating.
- Inspect the pump A control wire and harness for breaks, damage, or loose connections.
- Test continuity through the control circuit and pump motor, isolating components as directed by the manufacturer's wiring diagram.
- If the circuit is intact, use the manufacturer's procedure to verify the pump command and whether pump A operates.
Common fixes
- Reseat a pushed-back connector pin and secure the pump connector.
- Repair an open or damaged pump A control wire.
- Replace electronics coolant pump A if its motor circuit is open.
- Repair a control-side connection or component identified by circuit testing.
Can I keep driving?
Avoid driving if the vehicle shows a cooling warning, reduced power, or limited operation, because the power electronics may not receive adequate cooling. Stop safely if a warning escalates or power drops, and have the pump circuit checked promptly.
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.