Means the ESP isn't working.
But seriously, it's essentially just an ABS system with a turn angle sensor, very little than can be wrong with that. Have you got planet to test it?
When was the fuel filter last changed? Could be getting blocked if it works after priming? Otherwise an air leak sounds likely yeah.

When was the fuel filter last changed? Could be getting blocked if it works after priming? Otherwise an air leak sounds likely yeah.