9900 won't INIT FILL

I preparation for changing this 9900 to Piezography I loaded a set of carts filled with Piezo flush and put them in my 9900. Started it up in “Self Testing Mode”.
All inks showed 100% full in the screen.
Pressed MENU and selected CLEANING.
Selected INIT FILL.
When I hit Ok to start the init fill the pump came on for 1 second then turned off and the screen goes back to the Cleaning menu.
After this occurring a few times I tried a Std CL1 cleaning and the 9900 did that cleaning with no problem.
How can I get it to do the needed INIT FILL?

This means that your maintenance tank is not empty enough. Get a new one or reset yours if you have a maint. tank resetter.

Also, it means that your firmware is not up to date and does not say that your maintenance tank is too used. (I think I’ve done too many 9900 changes, can you tell?)