What it means
A general circuit fault on the position sensor of the third engine coolant bypass valve C - typically used in advanced thermal management systems with multiple coolant loops.
At a glance
- Usually lights the check-engine light
How it works
Coolant bypass valve C routes coolant through a particular path in the engine's thermal management system, and its position sensor reports how far the valve has moved. This code sets when the control module detects an open or otherwise faulty position-sensor circuit, so it may not know whether valve C reached the commanded position.
Common causes
Most likely first.
- Open or damaged wiring to the valve C position sensor
- Loose, corroded, or damaged connector
- Failed valve position sensor
- Fault in the valve actuator or control module
Symptoms
- Check engine light
- Coolant temperature fluctuates or runs outside its usual range
- Cabin heat is weak or inconsistent
- Engine takes longer to reach operating temperature
How to diagnose it
- Scan for related coolant temperature or valve codes and review freeze-frame data to see when the valve C position fault occurred.
- Compare commanded and reported valve C position, if available in live data, and check whether coolant temperature or cabin heat changes abnormally.
- Inspect valve C's connector and harness for disconnected plugs, corrosion, damaged insulation, or pulled-out pins.
- Check the position-sensor circuit continuity and connector contact against the manufacturer's wiring diagram and specification.
- Test the sensor supply, ground, and position signal at valve C to locate an open circuit or failed sensor.
- If the sensor circuit is intact, check whether the valve C actuator moves as commanded and whether its control module output is functioning.
Common fixes
- Reconnect or repair damaged wiring and connector pins at coolant bypass valve C.
- Replace the valve C position sensor if its circuit tests confirm sensor failure.
- Replace the coolant bypass valve C actuator or assembly if it binds or cannot report position correctly.
- Repair the valve driver or control module only if testing confirms its output is faulty.
Can I keep driving?
If temperature remains normal, you can generally make a short, monitored drive, but watch the temperature gauge and stop if the engine overheats. Incorrect coolant routing can cause weak cabin heat or poor temperature control, so arrange repair soon.
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.