What it means
The control module monitors the electrical circuit for coolant bypass valve C. It sets this code when it detects an open circuit that prevents the valve from being controlled as expected.
At a glance
- Usually lights the check-engine light
How it works
Coolant bypass valve C uses an electrically controlled actuator to regulate coolant flow through its path. This code indicates an open circuit in valve C's control circuit, such as a broken wire or an open solenoid coil, so the module cannot control the valve as expected.
Common causes
Most likely first.
- Open coil in bypass valve solenoid
- Broken control wire
Symptoms
- Check-engine light
- Engine temperature may fluctuate
- Heating or warm-up may be affected
How to diagnose it
- Review freeze-frame data and live coolant-temperature readings to see when the valve-control fault affects warm-up or temperature behaviour.
- With the engine cool, inspect valve C's connector and wiring for broken wires, loose pins, or corrosion.
- Check the valve C solenoid coil for an open circuit using the manufacturer's test procedure.
- Test continuity through the valve C control and return wiring, checking harness sections and connector pins.
- If wiring and the coil pass, verify the control module output according to the manufacturer's procedure.
Common fixes
- Reconnect a loose valve C connector.
- Repair a broken control wire or damaged connector pin.
- Replace valve C if its solenoid coil is open and not separately serviceable.
- Repair the control module circuit only after confirming the valve and wiring are intact.
Can I keep driving?
If the temperature gauge remains normal, short, gentle trips may be possible while you monitor it closely. Stop if the engine overheats or temperature fluctuates sharply, since valve C may not respond to commands and cooling or cabin heat can be affected.
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.