I just picked one of these Sonic mobility scooters up did the same flash 3 flashes then one found out it was the speedometer potentiometer the one that makes it go slow or fastby unplugging it also will make the unit run when installing a new one fix the code problem and made it run great

Test batteries to see if they full, the controller thinks either you need to charge the batteries or it is over charged. 2 beeps need charging, 3 beeps overvoltage.

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