What it means
The control module detects that the reductant heater coolant control valve is stuck closed. This can prevent the reductant heating system from operating as intended.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The reductant heater coolant control valve directs engine coolant through the reductant heating circuit when heating is needed. This code sets when the module detects that the valve is stuck closed, which can prevent the SCR reductant system from warming as intended, particularly in cold conditions.
Common causes
Most likely first.
- Valve mechanically stuck
- Valve control or wiring fault
Symptoms
- Check engine or SCR warning may be on
How to diagnose it
- Read freeze-frame data and related SCR codes to see when the valve fault was detected and whether cold conditions or reductant-heating faults are also reported.
- Inspect the reductant heater coolant control valve and its connectors for visible damage, coolant leaks, corrosion, or disconnected wiring.
- Check the coolant hoses serving the valve and reductant heater for kinks, leaks, or other visible restrictions.
- Use a scan tool to command the valve if the vehicle supports it, and observe whether its reported state changes as requested.
- Test the valve's control circuit and mechanical movement against the manufacturer's specifications before replacing parts.
Common fixes
- Reconnect or repair a loose, corroded, or damaged valve connector or wiring.
- Repair a leaking or restricted coolant hose in the reductant heater circuit.
- Free or replace the reductant heater coolant control valve if testing confirms it is stuck closed.
- Repair a confirmed valve-control circuit fault.
Can I keep driving?
You can often drive if the engine behaves normally and no SCR warning or operating restriction appears, but the reductant system may not heat properly in cold weather. Address the fault promptly because SCR warnings or restrictions may follow.
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.