I go through the same motions every time I change the batteries. Flashing numbers. Logo, blah blan blah..and then I click the power bar 5 times. Sometimes it will ask if it is a new coil as I always have a tank on it... I just took my batteries out and did it again without a tank. I'd suggest trying it with a tank on and trying it with a tank off, see if it reads the tank.
OR
Click the power button 3 times...the blutooth symbol wil show... Use the arrow keys to scroll to 6...the POWER icon. When it shows in the window hold down the power bar until it gives you the Option to turn it on. Use arrow keys to select ON