What it means
Voltage on the engine coolant pump control line is below the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The engine coolant pump circulates coolant to control engine temperature. P26CC sets when the pump control-line voltage is below the module’s expected range, which can result from a short to ground, an internally shorted motor winding, or poor connector contact.
Common causes
Most likely first.
- Control wire shorted to ground
- Motor winding short
- Connector pins corroded - high contact resistance
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 overheating is present, switch off the engine and let it cool.
- Scan for related cooling codes and review freeze-frame data and live pump command to establish when the low circuit reading occurs.
- With the engine cool, inspect the pump connector and harness for chafing, water entry, corrosion, or pushed-back pins.
- Wiggle the accessible pump harness while monitoring the active circuit reading to check for an intermittent short or connection fault.
- Using the manufacturer's procedure, test the control wire for a short to ground and the pump winding for an internal short, then verify the controller output if both pass.
Common fixes
- Clean and secure corroded or loose pump connector terminals.
- Repair control wiring shorted to ground or damaged by chafing or water entry.
- Replace the coolant pump if its motor winding is internally shorted.
- Repair the controller circuit if its output is confirmed faulty.
Can I keep driving?
Do not drive if the engine temperature rises or a cooling warning appears; a low pump-control circuit can prevent coolant circulation and lead to severe engine damage. Stop safely, switch off the engine, and let it cool before inspection.
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.