What it means
The control circuit of alternative fuel tank shutoff valve D reports a control circuit/open condition. Tank isolation cannot be commanded as expected on multi-tank CNG/LPG systems.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Shutoff valve D is the electrically controlled isolation valve for tank D in a multi-tank CNG or LPG system. The control module monitors the D circuit for an electrical path when it commands the valve. This code sets when that path appears open, for example from a broken wire, an open coil, or a terminal that has backed out of its connector.
Common causes
Most likely first.
- Open in valve control wire
- Open valve coil
- Pin pushed back out of connector body
Symptoms
- Check-engine light
- Alternative-fuel warning light
- Difficulty switching fuel modes
How to diagnose it
- Save freeze-frame data and check whether the open-circuit fault returns when the scan tool commands valve D.
- Inspect valve D's connector for a pushed-back pin, corrosion, or a loose fit, then trace its harness for breaks or damage.
- With the system disabled as specified by the manufacturer, check continuity through the valve D control circuit.
- Measure valve D's coil and compare it with the manufacturer's specification to determine whether the coil is open.
- If the circuit and coil are intact, check the control-module output with the vehicle's approved procedure.
Common fixes
- Reseat a backed-out valve D connector pin and secure the connector.
- Repair an open or damaged valve D control wire.
- Replace valve D if its coil is open.
- Repair the control-module circuit if testing confirms an output fault.
Can I keep driving?
Tank D may not be isolatable and fuel-mode switching may be limited, so follow the vehicle's alternative-fuel warnings and available-mode indicators. Stop using alternative fuel if the system reports a fault that prevents safe operation.
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.