The 23XI Racing driver was found to have breached the NASCAR Member Code of Conduct after he deliberately hit Grant Park 165 race winner Alex Bowman on the cool-down lap.
The hit was hard enough to sandwich Bowman up against the concrete wall, who raised his hands in confusion.
That followed an incident earlier in the race on lap 25 when Bowman hit Wallace into a spin.
Wallace hit the wall as a result and went on to finish 13th while Bowman rose up the field to win the rain-shortened race.
Bowman apologised profusely for the incident after winning Monday’s race.
“First off, like we talked earlier, I have to apologise again to the #23 guys,” said Bowman
“I just messed up trying to get my windshield wiper on, missed the corner and ruined their day.
“I hate that. I’m still embarrassed about it but we have a trophy to take home and I know it means a lot to this team.”
Wallace currently lies 17th in the playoff standings and 45 points below the cut-off to make the top 16.
The NASCAR Cup Series continues on Monday, July 15 with the HighPoint.Com 400 at Pocono Raceway.