The E06 code just means that the battery is empty.
You can cycle through the settings by just pressing the power button once turned on.
You will see the letter V (looks more like a U) where the mileage is usually displayed. This is the voltage.
Also, ensure that P03 and P15 is correctly set.
Horizon battery voltage and charge
Another possibility is that the charger is defective. Do you have a voltmeter at home? If you do, please measure the charger output - it should show 54.6V+
