What it means
The control module detects that the EVAP system vent valve remains open when it is expected to close. This can interfere with the system's ability to seal for leak testing.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP vent valve opens the charcoal canister to filtered air and closes when the system needs to seal for leak testing. This code sets when the module detects that the vent valve remains open when closure is expected, so the EVAP system may be unable to seal for its test.
Common causes
Most likely first.
- Vent valve mechanically stuck open
- Dust/debris preventing valve seat
- Carbon or debris buildup preventing free movement
Symptoms
- Check engine light on
How to diagnose it
- Review freeze-frame data and related EVAP codes to see when the system expected the vent valve to close.
- Inspect the vent valve, its air inlet, and nearby hoses for dirt or debris that could hold the valve open.
- Check the valve connector and harness for loose contacts or damage that could prevent the valve from being commanded.
- Use a scan tool to command the vent valve open and closed, if supported, and observe whether its response matches the command.
- Test the valve operation and control circuit against the manufacturer's specifications to confirm whether the cause is contamination, a stuck valve, or an electrical fault.
Common fixes
- Clear dust or debris from the vent valve inlet and seating area using the vehicle's specified service method.
- Repair a loose or damaged vent-valve connector or wiring.
- Replace the EVAP vent valve if it remains mechanically open after cleaning or fails an operation test.
- Repair a confirmed vent-valve control circuit fault.
Can I keep driving?
You can usually continue driving if the vehicle runs normally, but the EVAP system may not complete leak testing and the vehicle may fail an emissions inspection. Address the fault before an inspection or if fuel vapour odours develop.
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.