Arizona Summit Law school, a troubled for-profit institution owned by the InfiLaw System, has been placed on probation by its accrediting body, the American Bar Association. The association’s move was announced on Monday and followed Arizona Summit’s affiliation with Bethune-Cookman University, a nonprofit historically black college in Daytona Beach, Fla. Arizona Summit Law in Phoenix is the second school owned by InfiLaw to be placed on probation for failing to meet A.B.A. accreditation standards. Sterling Partners, a private equity firm in Chicago and Baltimore, is an investor. The first, Charlotte School of Law in Charlotte, N.C., lost its eligibility for federal student aid in January as a result of the probation. Its enrollment has declined sharply, and the school has said it is trying to restart federal aid and is exploring affiliation with a nonprofit college in a Northeastern state. At Arizona Summit, the bar association found that admissions practices, academic programs, and graduation and bar exam passage rates were below par. These deficiencies, according to a statement by the A.B.A. Section of Legal Education and Admissions to the Bar, “have resulted in the law school now being in a position where only immediate and substantial action can bring about a sufficient change to put the law school on a realistic path to being in compliance within the time allowed” by the bar association’s rules. Only 24.6 percent of Arizona Summit graduates who took the Arizona state bar exam for the first time in July 2016 passed, an exceptionally low rate. Charlotte School of Law reported nearly the same passage rate for its graduates who took the North Carolina bar exam last month. The bar association said that because the situation at Arizona Summit was critical and urgent, it could have hearings this year to consider any additional remedial action or sanctions “up to and including withdrawal of the law school’s approval.” The probation decision was made by the bar association’s Council of the Section of Legal E