Der Fehler weist prinzipiell auf einen „fehlerhaften“ Jet Pump Valve Actuator hin, welcher den Output der Jet Pump steuert:

Hierzu besteht jedoch auch ein aktuelles TFU, welches den Fehler als Spurious beschreibt (siehe anbei). Technischer Hintergrund ist, dass sich der Actuator bei jedem Power Switching ein Stück von seiner closed Position wegbewegt und irgendwann kein Sensorkontakt mehr besteht. Der Fehler verschwindet, sobald der Actuator gecycled wird:

“The fault message is still found to be caused by the loss of the Transfer Control Valve FULLY CLOSED feedback signal, though the root cause of the loss of feedback signal has changed. Testing shows in flight phase 2 that with the actuator in the closed position, an interruption of power causes the actuator to move a small amount away from the closed position. This interruption of power is suspected to be predominantly caused by a power transition (from APU power to engine power). After a series of power switches, the accumulated movement may cause the actuator to no longer indicate a FULLY CLOSED position and lead to the noted fault messages. This explains the reason why the faults are predominantly observed on aircraft operating with their center tank empty for extended time period. Indeed, if the center tank is used, it should reset the actuator position and prevent the message from occurring.”

TFU 28.26.00.008