James Hinchcliffe’s car failed post-race checks after the Firestone 600 in Texas, with his Schmidt Peterson Motorsports team picking up penalties.
His IndyCar entry was found to be in violation of rule 14.6.8.2.2 of the IndyCar rules, relating to domed skid wear.
Schmidt Peterson Motorsports was handed a $20,000 fine and both the team and Hinchcliffe were docked 25 points for the regulations breach.
Hinchcliffe was beaten by just 0.008 seconds by Graham Rahal to the Firestone 600 victory, in the rescheduled race.
“In our post-race analysis this week it was determined the skid plate on the No. 5 entry was worn and in violation of our rules," said IndyCar president of competition and operations, Jay Frye.
"This was both a performance advantage and a safety concern, as the domed portion of the skid had been ground down to the point it would have been ineffective."
The points deduction drops Hinchcliffe one spot to ninth in the IndyCar championship, with two rounds left to go.
