"In the spring of 2014 when the West Virginia University study was published, I was told that there was a possible emissions non-compliance that could be remedied," Michael Horn said in a written testimony published on the company's website. The statement included an apology for what it termed "deeply troubling" actions by the car maker.
Horn is expected to present testimony before the House Committee on Energy and Commerce and Subcommittee on Oversight and Investigations later in the day.
"I was informed that EPA [Environmental Protection Agency] regulations included various penalties for non-compliance with the emissions standards and that the agencies can conduct engineering tests which could include 'defeat device' testing or analysis," he added.
Volkswagen Germany CEO Matthias Muller said on Tuesday that the company planned to begin a recall of cars involved in the emission scandal.