Geni e Z45/25J Driving fast foreward just slows down

Hi. I have a Genie Z45/25J with a Perkins motor, sn# Z452514A-50998. While driving forward in fast mode for a couple of yards, it just slows down to turtle speed. There is no error message except the regeneration active indication. Any help will be appreciated.

Geni e Z45/25J Driving fast foreward just slows down