Definition
Preventive maintenance, or PM, is maintenance done on a schedule before a failure, rather than after. A PM service typically combines fluid and filter changes, lubrication, adjustments, and an inspection of safety and wear items. Intervals are usually set by miles, engine hours, calendar time, or fuel used, based on the manufacturer recommendations and the fleet duty cycle.
The regulatory link
49 CFR 396.3(a) requires every motor carrier to systematically inspect, repair, and maintain all vehicles under its control. Section 396.3(b)(2) requires records that include a means to indicate the nature and due date of the various inspection and maintenance operations to be performed. A PM schedule is the most common way fleets meet that requirement. Section 396.5 adds that vehicles must be properly lubricated and free of oil and grease leaks.
A, B, and C services
Many fleets use lettered levels. A PM A is usually the shortest service, a PM B adds more items, and a PM C is the most complete. There is no federal definition of these levels. Each fleet or shop defines what is in each one, so write the contents down and share them with the customer. See PM A, PM B, and PM C.
PM is not the annual inspection
The DOT annual inspection under 396.17 is a separate federal inspection against Appendix A. Shops often do both on one visit, but should record them as separate lines.
Shop angle
PM work is predictable revenue and keeps fleet customers coming back. Track due dates by unit, send reminders, and record meter readings at every visit. MetaFleet supports PM programs, reminders, and booking through the customer portal; see preventive maintenance. For building a program, read how to run a PM program for a fleet.