Park Geun-Hye apologised to the public as she arrived at the prosecutors' office in Seoul, adding: "I will undergo the investigation sincerely".
South Korea's first female president, Park was impeached by parliament in December as millions of people took to the streets to demand her removal over the sprawling scandal, which has exposed the links between politics and business in Asia's fourth-largest democracy.
Her dismissal was confirmed by the country's top court earlier this month, ending the political career of a woman who grew up in the presidential palace as the daughter of army-backed dictator Park Chung-Hee.
A private citizen once again, Park's convoy drove at walking pace through crowds of flag-waving supporters lining the street outside her home, before speeding up.
Every inch of the short journey was covered live on television, with cameramen trailing the group in cars and on motorcycles, and at fixed points along the route.
Watch: South Korea's impeached president arrives for questioning
