Top 5 KPIs for Fleet Maintenance Managers

If you're not measuring it, you're not managing it. That’s especially true in trailer maintenance, where a few overlooked metrics can create ripple effects that hit everything from uptime to budget to CSA scores. The right fleet maintenance KPIs help managers track performance, spot inefficiencies, and keep operations tight.

Here are five of the most important metrics every fleet maintenance manager should be tracking — and how diagnostic tools like the Inspector 930 and Sentry Software can help improve them.

1. Preventive Maintenance Compliance Rate (PM Compliance)

This measures how consistently trailers receive scheduled preventive maintenance on time. If your PM compliance is below 90%, you're leaving your fleet open to failures, road calls, and DOT violations.

Sentry Software gives you the tools to schedule and verify PMs across your trailer assets, while the Inspector 930 ensures every inspection hits every system — lighting, air, and ABS.

2. Mean Time Between Failures (MTBF)

This tracks the average time or mileage between unscheduled breakdowns or component failures. A rising MTBF indicates better performance and reliability. A declining MTBF signals systemic issues, often tied to gaps in diagnostics or missed patterns.

By logging trailer diagnostics consistently with the Inspector 930 and storing results in Sentry, managers can identify weak links and correct them before failure strikes.

3. Repeat Repair Rate

When the same trailer comes back with the same issue, that’s a red flag — and a cost center. This KPI tracks how many repairs are rework or repeat jobs, which often stems from incomplete or inaccurate diagnostics.

The Inspector 930’s full-system testing reduces the guesswork, ensuring techs address the real problem the first time — not the symptom.

4. Downtime Per Trailer

Knowing how many hours (or days) each trailer is out of service per month is essential. High downtime = lost productivity and load capacity. But many shops don’t track this at the trailer level, only at the truck level.

Sentry helps fleets track diagnostic test dates, repairs, and return-to-service timelines — giving you clear visibility into asset availability and trailer performance over time.

5. Cost Per Mile for Maintenance

This big-picture KPI rolls together parts, labor, diagnostics, and downtime into a single number that tells you how efficiently your shop is running. If your cost per mile is rising, something is off — and it’s time to dig into where labor is being wasted or where diagnostics are falling short.

Accurate diagnostics = fewer wasted hours, fewer parts thrown at the wrong problem, and fewer breakdowns.

What Gets Measured Gets Fixed

You can’t improve what you don’t track. These fleet maintenance KPIs give managers the visibility they need to stay in control — and tools like the Inspector 930 and Sentry software provide the data to back it all up.

Want to see how these KPIs look across your fleet? Visit Lite-Check.com, call 509-535-7512, or email info@lite-check.com to talk about getting started.