Rationale: The first issue of J817-1 (issued 1962-04) included a diagram that had an element called "Diagnostics". The second issue of J817-2 deleted this diagram and rather focused on defining a Maintainability Rating Index. The 3rd issue of J817 had it's Scope defined as "This SAE Information Report establishes a point system that encourages ease of maintenance actions on off-road
machines. The point system minimizes subjectivity in evaluating maintainability as defined in ISO 8927". This 4th revision seeks to add a Diagnosability Rating Index with Point System to J817.