The U.S. Federal Trade Commission will be looking into complaints that Volkswagen AG engaged in deceptive advertising with its “clean diesel” marketing campaign.

The print and television ads in question prominently describe VW’s powertrain as “TDI Clean Diesel.” Many of the commercials directly address perceptions that diesel is slower, louder and smellier than a gasoline-powered engine.

The TDI engine is “painstakingly engineered without compromise to be more powerful and miraculously unleash 46 mpg highway,” noted one television ad.

“Volkswagen’s claims about the environmental impact of its vehicles were false,” said Senator Bill Nelson. In an open letter to Edith Ramirez, chairwoman of the FTC, the senator asked the FTC to look further into Volkswagen’s “unfair or deceptive acts or practices.”

“Volkswagen advertised their diesel cars as ‘clean diesel’ and as otherwise environmentally friendly,” Nelson wrote in his letter. “Yet, contrary to these express claims, Volkswagen’s and Audi’s diesel vehicles, by design, were neither clean nor environmentally friendly, and they failed to comply with federal environmental laws.”

“I am outraged that VW would cheat its customers by deceiving them into buying a car that wasn’t what was advertised,” he continued. “As such, I ask that the commission explore possible remedies under the FTCAct to remedy consumers who relied upon Volkswagen’s deceptive claims.”

Senator Nelson suggested that the FTC force VW to run a “corrective marketing campaign” to notify the public about the problem and explain how the carmaker will correct it.

Almost 90 consumers have also directly filed complaints through the FTC’s Consumer Sentinel Network; many write that they feel deceived and regret owning a diesel with such high emissions. Others worry that they will be unable to sell their cars because of the scandal.

“I am ashamed to drive this car on the road, as doing so is evidence that I have been taken for a fool,” said one consumer from Dripping Springs, Texas.

“Consumers who are environmentally mindful like those who purchased VW ‘Clean Diesel’ cars should be reimbursed before fines are paid to the EPA,” wrote another consumer. “The EPA doesn’t need money, but I do. … I would have never bought a VW if it wasn’t good for the environment.”

SEE ALSO: Daimler Agrees To Let Volkswagen Hire Its Compliance Expert

Volkswagen hasn’t elaborated on the investigations from the FTC, the U.S. Environmental Protection Agency or the Justice Department, but did say the company is attending to all of the concerns.

“We have been cooperating with all of the agencies that have come to us,” said Volkswagen representative Jeannine Ginivan. “Our primary focus is addressing the matter at hand and making things right for our customers, dealers and employees. Once the diesel models have final certification from the EPA and become available for sale, we plan to return them to our website and other advertising platforms.”