Hyundai announced Monday that the fuel economy of its revamped Sonata sedan was less than what had been stated previously in publicity material for the media earlier this month.

Hyundai, the world's fifth-largest car maker, said Monday that it overstated the gas mileage of its revamped Sonata sedan in publicity material released for the media earlier this month. The car maker, however, realized it was an error and said that the results included in the media presentation were from company's internal testing at the research labs. This impacts consumer's reliability on the car maker after series of lawsuits in relation to overstated mileage kept Hyundai busy in the past.

The error came to light after the government tested the vehicle and announced Friday that the actual mileage of the upcoming Sonata was 12.1 kilometers per liter (28.4 miles per gallon), instead of 12.6 kilometers per liter (29.6 mpg) as Hyundai stated. But the company's vice president Hwang Chung-yul said the new Sonata sedan had an improvement of 6 percent in fuel economy compared to its previous model. The current Sonata sedan is said to achieve 11.9 kilometers per liter, according to Hyundai.

"We are very sorry for causing confusion to reporters," Hyundai said in a statement, according to Reuters.

Hyundai, South Korea's largest car company has made several appearances in the court with regards to customer lawsuits claiming the South Korean car maker and its affiliate Kia Motors overstated the fuel economies on 900,000 vehicles sold in the U.S. The two companies also agreed to pay $395 million to consumers as a part of settlement.

Hyundai Sonata has been in the company's books since 1985, but underwent series of facelifts. The upcoming Sonata model is the first since 2009, when the company launched its sixth generation model. Hyundai is set to launch the new model in South Korea later this month and said it already began receiving pre-orders since the first media release.