IndyCar Series champion Scott Dixon was initially shown as the winner of the season's final race because of a faulty transponder on his race car, the Indy Racing League said Monday.

The electronic timing showed Dixon was the winner of Sunday's PEAK Indy 300 at Chicagoland Speedway, but race officials studied photos of the finish and gave the victory instead to Helio Castroneves. The margin was 0.0033 seconds, the second-closest finish in IRL history.

"The improperly installed transponder clearly affected the data we were receiving from Dixon's car," IRL timing and scoring director Jon Koskey said. "With the signal going the wrong direction, it could have bounced off of any number of things and made it difficult for the antenna to pick up an accurate signal."

The IRL timing system is backed up by a high-speed camera that takes a picture every ten-thousandth of a second.

After the race, the camera operator told race stewards that the photos showed Castroneves in front at the finish line, and IRL president Brian Barnhart reviewed the photos and confirmed Castroneves was the winner. By that time, Dixon had already gone to Victory Circle to celebrate both the race win and the series championship.

"It was the craziest Victory Circle I've been involved in, where you see your car rolled into position, you get out like you won the race and they roll it off and take your hat off you and say you haven't won," Dixon said Sunday after the mistake was corrected. "That was tough to deal with but, in the back of my mind, we all knew we'd won the championship, and that was the main goal."

The second-place finish left Dixon 17 points ahead of Castroneves for the IndyCar championship, his second IRL title.

The only closer race in the 13-year history of the series was Sam Hornish Jr.'s 0.0024-second win over Al Unser Jr. in 2002 on the same Chicagoland track.

"We've invested hundreds of thousands of dollars in this system since 2001 to make sure our timing systems are accurate and provide the officiating staff with the information necessary to make good judgment calls such as this," Barnhart said.

The IRL's timing and scoring system is the only one in motorsports that scores to ten-thousandths of a second.

"We use the high-speed camera to review the finishing order of every car at every race. It's not always that close between the top two cars, but we have close finishes further back in the field all of the time," Barnhart said.

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