Baker Tilly senior manager Matthew Wild said the b2b online used car stock locator business had run out of funding after failing to reach a cash break-even point.
"We are trying to sell the technology to interested parties," he said. "The staff have been made redundant and we are also in the process of selling the property."
Auto Online was launched in 1999 with backing from several venture capitalists.
Despite operating a 'no sales success, no fee' system, inside sources said few dealers signed up to the service - Auto Online had initially targeted 4,000.