What it means
Hybrid/EV electronics coolant pump C does not produce the expected flow. Pump aging or air pocket in loop.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Electronics coolant pump C circulates coolant through a hybrid or EV power-electronics cooling loop. The control module checks whether the pump produces the expected cooling performance; this code sets when flow or cooling response is inadequate, which can allow power electronics to overheat.
Common causes
Most likely first.
- Pump output degraded
- Coolant level low
Symptoms
- Check-engine or hybrid-system warning light
- Reduced power or limited hybrid operation
- Possible power-electronics overheating warning
How to diagnose it
- Use a scan tool to save freeze-frame data and check for pump C commands, temperature readings, and related cooling-system faults.
- When the system is cool, check the relevant coolant reservoir level and look for visible leaks that could leave pump C's loop low.
- Inspect accessible pump C wiring and connectors for damage or a loose connection, and confirm whether the pump operates when commanded using the manufacturer's procedure.
- Check the cooling loop for signs of trapped air and verify that the pump is moving coolant as specified by the manufacturer.
- If coolant level, wiring, and air in the loop are ruled out, test pump C's flow or performance against the manufacturer's specification.
Common fixes
- Correct a low coolant level and repair any leak found in pump C's loop.
- Bleed trapped air from the loop using the manufacturer's procedure.
- Repair a damaged or loose pump C connector or wiring.
- Replace pump C if it cannot meet the manufacturer's flow or performance specification.
Can I keep driving?
Limit driving if power is reduced or a power-electronics overheating warning appears; continued operation with inadequate cooling can damage electronics. Stop safely if an overheating warning occurs.
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.