Charlotte, NC (SportsNetwork.com) - Jimmie Johnson's No. 48 team avoided penalties but did receive a written warning from NASCAR on Tuesday for altering the side skirts on their car during last Saturday night's NASCAR Sprint All-Star Race at Charlotte Motor Speedway.

Prior to the start of the 2015 season, NASCAR made a rule modification that prohibited Sprint Cup Series teams from flaring the side skirts -- the sheet metal ahead of the rear tires on the car -- during pit stops in a race. It had the potential to improve air flow over the rear of the car, which would help increase speeds. The practice became widespread in Sprint Cup during the latter half of the 2014 season.

NASCAR will issue a warning to any team in their first offense of altering the side skirts and then assess penalties if there are repeat offenses.

Johnson, the six-time Sprint Cup champion, finished 15th out of the 20 drivers who participated in the all-star race, which is a non-points event.

Also on Tuesday, NASCAR handed down penalties to JR Motorsports' No. 00 team in the Camping World Truck Series for a rules infraction discovered in last Friday's race at Charlotte Motor Speedway. Kasey Kahne's race-winning truck measured too low on both sides of the front and too high on the right-rear corner.

Crew chief Joe Shear Jr. received a $6,000 fine and was placed on probation until Dec. 31. Dale Earnhardt Jr. was docked 10 owner points in the Truck Series. Kahne, a Sprint Cup Series regular, did not receive a loss of points since he is not competing for the championship in trucks. He won the race by only a 0.005-second margin over Erik Jones.

The No. 4 JD Motorsports team, with driver Ross Chastain, in the Xfinity Series received penalties for a rules violation that occurred during last Saturday's practice at Iowa Speedway.

Crew chief Gary Cogswell was fined $15,000 and placed on probation for the remainder of the year, while car chief Charles Kent was put on probation for the same period of time as Cogswell because of improperly attached weight on Chastain's Xfinity car.