Direct Answer
The most common Vehicle Maintenance BASIC violations are brake defects, lighting failures, and tire issues, all of which can trigger Out-of-Service orders. Each one counts against your Vehicle Maintenance BASIC score in the FMCSA's CSA system and stays on your record for 24 months.
What This Means
The Vehicle Maintenance BASIC is the most-cited category in FMCSA roadside inspections. It covers the mechanical and physical condition of commercial motor vehicles: brakes, tires, lights, steering, suspension, coupling devices, frames, and more.
Violations range from a burned-out marker light (low severity, no OOS) to brake failure on a loaded axle (high severity, immediate OOS). Understanding which violations are most common, and which are most dangerous to your CSA score, lets you focus your preventive maintenance exactly where it counts.
Regulation Context
- Primary CFR: 49 CFR Part 393: Parts and Accessories Necessary for Safe Operation
- Brakes: 393.45–393.52
- Tires: 393.75
- Lighting: 393.9–393.33
- Steering: 393.209
- Coupling devices: 393.70–393.71
Top 10 Vehicle Maintenance Violations by Inspection Frequency
| Rank | Violation | CFR Reference | OOS? | CSA Severity Weight |
|---|---|---|---|---|
| 1 | Inoperative/defective brakes | 393.45 | Often | 10 |
| 2 | Brake adjustment out of limits | 393.47 | Yes (if multiple axles) | 8–10 |
| 3 | Tires, tread depth below minimum | 393.75(a)(3) | Yes (steer axle) | 8–10 |
| 4 | Inoperative turn signal | 393.19 | No | 3 |
| 5 | Inoperative brake/tail light | 393.9 | No | 5 |
| 6 | Inoperative headlight | 393.9 | Conditional | 5–8 |
| 7 | Cracked/broken windshield (vision obstructed) | 393.60 | Conditional | 5–8 |
| 8 | Air brake system leakage | 393.45 | Yes | 10 |
| 9 | Failing coupling device / fifth wheel | 393.70 | Yes | 10 |
| 10 | Inoperative/defective wipers | 393.78 | No | 3 |
Severity & OOS Impact
Brake violations are the highest-risk category. Brake defects account for the majority of OOS vehicle orders at roadside inspections. FMCSA uses the CVSA brake adjustment limits as the OOS threshold.
Tire violations on the steer axle are automatic OOS. Tread depth below 2/32 inch on a steering axle means the vehicle does not move.
Lighting violations rarely trigger OOS but quickly accumulate severity. Multiple lighting violations across inspections add up in your Vehicle Maintenance BASIC percentile and are often viewed as evidence of poor maintenance culture.
CSA / BASIC Impact
- BASIC affected: Vehicle Maintenance
- Severity range: 1–10 (OOS violations always score 8–10)
- Time on record: 24 months
- Alert threshold: Carriers above 80th percentile are at risk for FMCSA intervention
Brake and tire OOS violations are the fastest way to push a carrier's Vehicle Maintenance BASIC into alert territory. Lighting violations, while lower severity individually, frequently appear in clusters.
Corrective Action Steps
For every Vehicle Maintenance violation:
- Fix the defect before the vehicle returns to service.
- Document the repair with a work order: date, defect, parts replaced, technician.
- Conduct a fleet-wide sweep for the same defect type within 48 hours.
- Update your preventive maintenance schedule if the defect indicates a maintenance interval problem.
- Review the driver's pre-trip inspection log for the day of the violation.
- Brief the driver on what was found and why it matters.
Specific steps by defect type:
- Brakes: Perform full brake adjustment and lining inspection on all axles. Record readings. Set a recurring brake inspection interval.
- Tires: Full fleet tire audit with tread depth readings for every axle position recorded.
- Lights: Inspect all lights on all vehicles. Replace all burned-out bulbs. Check wiring and connectors on older vehicles.
Evidence Checklist
- ☐ Original inspection report
- ☐ Repair work orders for each defect cited
- ☐ Fleet-wide sweep results for the same defect category
- ☐ Updated PM schedule showing revised inspection intervals
- ☐ Driver pre-trip inspection log from day of violation
- ☐ Technician certifications if brake repairs were performed
Prevention Tips
Brake inspections should be a standalone PM item, not just a checkbox. Measure slack adjuster travel, record it, and compare to previous readings.
Build a lighting inspection into every pre-trip. Give drivers a specific checklist: headlights, taillights, brake lights, turn signals, marker lights, reflectors. Each light, individually.
Track violations by vehicle. A truck that generates repeated violations is telling you it needs more frequent PM, not just reactive repairs.
Frequently Asked Questions
Q: How many brake violations trigger OOS? CVSA sets specific thresholds based on the number of brake chambers out of adjustment relative to the number of braking axles. Generally, if more than 20–25% of braking capacity is impaired, the vehicle is placed OOS.
Q: Can we challenge a lighting violation if the light worked when we checked it? You can submit a DataQs challenge with documentation showing the light was functional at the last pre-trip inspection. Photographic evidence of a recent inspection helps.
Q: Do lighting violations count less than brake violations in CSA? Yes. Brake and tire OOS violations have severity weights of 8–10. Inoperative turn signals and non-critical lighting violations score 3–5. But multiple low-severity violations in one inspection still add up.
Q: How do we know which Vehicle Maintenance violations are hurting us the most? Review your FMCSA SMS data at ai.fmcsa.dot.gov. Your Vehicle Maintenance BASIC detail shows every violation by type and its contribution to your score.