The Hendrick Motorsports teammates hold down the top two spots in the Chase standings, with Johnson leading Martin by 12 points.
Johnson's No. 48 Chevy cleared a post-race inspection after winning the Pepsi 500 Sunday at Auto Club Speedway. The winning car and the engines of the top two finishing cars always are taken to the R&D Center.
Johnson won at Dover, Del. two weeks ago and Martin was second. After closer inspection at Concord, both teams were warned about being too close to the edge of the allowed tolerances at several places on the car bodies.
Martin finished seventh last week at Kansas and Johnson was ninth, but both cars again were taken the R&D Center. Both cars were cleared after inspections in Concord.
Martin finished fourth Sunday, but NASCAR officials again elected to take the No. 5 Chevrolet back to the R&D Center for additional tests.
Terry Blount covers motorsports for ESPN.com.