What it means
The controller cannot drive the main electric coolant pump. Without flow the engine and aftertreatment will overheat under load.
At a glance
- Usually lights the check-engine light
How it works
The engine coolant pump circulates coolant through the engine and, on some vehicles, related thermal-management components. P26CA sets when the controller detects an open pump control circuit and cannot operate the pump, which can stop coolant flow and allow temperatures to rise.
Common causes
Most likely first.
- Open pump motor winding
- Broken control wire to the pump
Symptoms
- Check-engine light may be on
- Engine temperature may rise or overheat
- Cooling-system warning may appear
How to diagnose it
- Check the temperature gauge and cooling warnings first; if the engine is overheating, switch it off and let it cool before inspection.
- Scan for cooling-system codes and review freeze-frame data to see the temperature and pump command when the circuit fault occurred.
- With the engine cool, inspect the pump connector and harness for disconnection, heat damage, broken wires, or corrosion.
- Test the pump motor winding for an open circuit using the manufacturer's procedure and specification.
- Check control-circuit continuity between the pump and controller, then verify controller output if the wiring and pump pass.
Common fixes
- Reconnect or clean a loose or corroded coolant pump connector.
- Repair a broken pump control wire or damaged terminal.
- Replace the coolant pump if its motor winding is open.
- Repair the controller circuit if its output is confirmed faulty.
Can I keep driving?
Do not continue driving if the temperature rises or an overheating warning appears; stop safely and switch off the engine, since loss of coolant circulation can cause severe engine damage. Never open the cooling system while it is hot.
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.