McLaughlin finished third in St. Petersburg while team-mate Josef Newgarden took the win, but both drivers were disqualified for illegally being able to use push-to-pass on the restarts.
Will Power, who drives the third entry for Team Penske, received a 10-point penalty but was not disqualified after it was discovered he did not use the overtake system on the restarts.
Defending his actions and those of his team, McLaughlin said: “First and foremost, I am proud to be a member of Team Penske.
“I fully stand with everyone one of my team-mates. Simply put, a mistake was made.
“I have the highest level of integrity and it is important to protect both my own reputation and that of the team.
“I was not aware of the situation with the software. In this instance, I used a single, very brief (1.9 second) deployment of push to pass in a section of the track exit of Turn 9 where it is typically utilised throughout the race.
“I hit the button out of habit, but I did not pass any cars nor did I gain any time advantage.
“IThe data, which IndyCar has, confirms all of this information. While I accept the penalty, I want to be clear that I did not gain an advantage over my competitors.
“IndyCar’s competition is the best in the world and I would take no pleasure in achieving success in any way other than honestly.
Source: Autosport