Where PM A fits
Many fleets and shops group preventive maintenance into levels, often called PM A, PM B and PM C. PM A is the lightest and most frequent level. PM B adds more inspection and service items, and PM C is usually the most complete. The letters are a trade convention, not a legal standard, so one shop's PM A may not match another's. Always read the written checklist rather than assuming what the letter means. See PM service.
What a PM A often includes
The exact list comes from the fleet's program and the vehicle maker's schedule. A typical PM A checklist may cover:
- Engine oil and filter change, with the oil type and quantity recorded.
- Chassis lubrication at every grease point.
- A walk-around check of lights, reflectors, mirrors, glass and wipers.
- Tire condition, inflation and tread depth. See tire tread depth.
- Brake check, including pushrod stroke and lining condition where visible. See slack adjuster.
- Fluid levels, belts, hoses and visible leaks.
- Any open driver-reported defects.
What the rules say
Under 49 CFR 396.3, a motor carrier must systematically inspect, repair and maintain its vehicles, keep a means to indicate the nature and due date of inspection and maintenance operations, and keep records of the work. The rule does not set a mileage interval or define service levels. A written PM A checklist and interval is one practical way to meet the systematic requirement.
How shops record it
Record the unit number, odometer reading or engine hours, each checklist item with a pass or fail result, the measurements taken, the parts and fluids used, and any defects found. Defects that need more work should become separate repair lines with their own approval. See estimate approval.
Example only
As an illustration, a fleet might schedule PM A at a set mileage and every second or third PM A becomes a PM B. The real interval should come from the fleet and the engine maker.
Related: PM B service, PM C service, preventive maintenance interval.
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