Turkish State Railways said nobody was hurt when the test run ended with the new train smashing into the rear of a work vehicle on the tracks.
The line between Turkey's two largest cities, its financial centre Istanbul and capital Ankara, is one of a number of ambitious projects embarked upon by the government.
The 250 km/h trains are due to cover the 450-km (280 mile) distance in 3-1/2 hours.
Erdogan, who has relied heavily on infrastructure investment to drive the economy and win political support, is expected to cut the ribbon on July 11. The opening has been delayed by several months and he has blamed setbacks to the project on sabotage.
A previous attempt to link the two cities with a high speed rail-link turned sour when a train derailed in July 2004, killing 41 people.