Chevrolet on Friday denied any knowledge of the IndyCar cheating scandal within Team Penske and said it had hired an independent law firm to investigate whether General Motors employees were involved.
General Motors president Mark Reuss said the manufacturer respects the "decision and actions" of IndyCar after last week's disqualifications of winner Josef Newgarden and Penske teammate Scott McLaughlin from the March 10 season-opening race.
IndyCar, nearly two months after the race, discovered that the push-to-pass software system on all three Penske cars had been manipulated to override series rules and allow the drivers to use the horsepower boost during restarts.
The series has not released the data, but reigning Indianapolis 500 winner Newgarden said he used the P2P button improperly three times and assumed because it worked that there had been a change to the rules. McLaughlin, who was stripped of his third-place finish, said he pressed the button once out of habit but gained no on-track advantage.
Will Power, fined because his car had the same software but not accused of any wrongdoing, said he never touched the button on starts or restarts because he knew it was against the rules.
The issue was discovered during the morning warmup ahead of the April 21 race at Long Beach when a glitch knocked out the software for every car except the three Penske entries.
Team Penske maintains that the newer software was used in August for hybrid engine testing and that its removal for the 2024 race cars was overlooked. The hybrid systems won't be introduced for competition until after the Indy 500.
Penske rivals have said they are insulted by the team's explanations, that they firmly believe Newgarden's team was cheating all along, and that far too much data exists for no one at Penske or Chevrolet to have noticed the software was wrong.
"My opinion is they knew exactly what they had," Andretti Global owner Michael Andretti said on Kenny Wallace's podcast this week, adding that he wished Team Penske had been more forthcoming about what it did.
Reuss said Friday that "Chevrolet engaged a third-party law firm to conduct a thorough review of the matter, and they found no evidence that any Chevrolet employee had any knowledge of or involvement in the matter." He added that Chevy will work with IndyCar and its partner teams to assist in aiding the integrity of the series.
IndyCar is owned by Roger Penske, who also owns Team Penske and the Indianapolis Motor Speedway. Roger Penske, 87, has denied any knowledge of the P2P scandal, and Newgarden said that Penske, his boss, "interrogated" him when IndyCar alerted the team to the disqualification.
Newgarden, a two-time series champion, is in a contract year with Penske. He is scheduled to be feted Saturday at the Kentucky Derby as the reigning Indy 500 winner. Then it is on to Indianapolis Motor Speedway for three consecutive weekends of racing leading into the Indy 500 on May 26.
The Associated Press contributed to this report.