What it means
The control module monitors coolant flow through valve C in the high-voltage battery pack cooling circuit and detects whether the valve responds to commands. It sets this code when the valve remains in the on state when it should change state.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Valve C routes coolant through part of the high-voltage battery pack cooling circuit. The control module commands the valve and checks whether its position or the resulting coolant flow changes as expected. This code sets when valve C stays on after the module commands it to switch off.
Common causes
Most likely first.
- Valve stuck open
- Driver stuck on
- Carbon or debris buildup preventing free movement
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Use a scan tool to save freeze-frame data and check valve C commands, reported position, and battery temperatures to see when it failed to respond.
- With the vehicle powered down as directed by its service information, inspect valve C and its coolant hoses for leaks, damage, or signs of restricted flow.
- Check the valve connector and accessible wiring for corrosion, loose pins, chafing, or damage that could keep the valve energized.
- Use the scan tool's available actuator test to command valve C on and off, and observe whether its reported state or coolant flow changes.
- If the command reaches the valve but it remains on, test valve movement and the control circuit using the manufacturer's procedure before replacing parts.
Common fixes
- Repair a loose, corroded, or damaged valve C connector or wiring.
- Clear debris or deposits restricting valve C movement, if serviceable.
- Replace valve C if it sticks despite correct commands and circuit operation.
- Repair the valve driver circuit if testing confirms it is holding valve C on.
Can I keep driving?
Avoid demanding acceleration, long trips, and charging if the vehicle reports reduced power or a battery cooling warning; poor battery cooling can lead to further power limits or charging restrictions. Stop safely if a high-voltage system warning escalates or the vehicle becomes difficult to control.
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.