Abstract: A method of monitoring a fluid supply is provided, the fluid supply including a supply tank, an intermediate tank and a fluid pump operatively coupled to the supply tank and the intermediate tank; the method comprising with the intermediate tank having a defined first fluid level, starting to feed fluid from the intermediate tank; when a defined amount of fluid has been fed from the intermediate tank, with the feeding of fluid from the intermediate tank proceeding, activating the fluid pump to supply fluid from the supply tank to the intermediate tank; monitoring the fluid level of the intermediate tank while the fluid pump remains activated; and diagnosing operation of the fluid pump as a function of the fluid level of the intermediate tank.