What it means
The engine coolant flow control valve reports a control circuit high condition. Coolant routing between engine and radiator branches cannot be commanded as expected.
At a glance
- Usually lights the check-engine light
How it works
The coolant flow control valve motor routes coolant between engine and radiator branches. The module detects control-circuit voltage higher than expected; a wire shorted to battery voltage, an open motor, or a high-resistance connector can cause this high reading.
Common causes
Most likely first.
- Control wire shorted to B+
- Open valve motor
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Engine may take longer to warm up or run hotter than usual
- Cabin heat may be weak or inconsistent
How to diagnose it
- Use freeze-frame and live coolant-temperature data to establish when the high circuit condition occurred and whether warm-up or temperature control changed.
- With the engine cool, inspect the valve harness for insulation damage that could expose it to battery voltage and check connector pins for corrosion or looseness.
- Check the valve connector and motor for an open connection or winding, which can leave the control circuit reading high.
- Command the valve with a scan tool if available and monitor the reported circuit state and valve response.
- Test the control wire for a short to battery voltage and check the motor and connector against the manufacturer's specification.
Common fixes
- Repair a control wire shorted to battery voltage.
- Clean and secure corroded or loose valve connector terminals.
- Replace the coolant valve motor or assembly if testing confirms it is open.
- Verify commanded valve movement and normal temperature behavior after repair.
Can I keep driving?
Use only short, gentle trips while monitoring the temperature gauge, since the valve may not route coolant as commanded. Stop if the engine runs hot or a temperature warning appears; overheating can cause major engine damage.
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.