CSA
Search
Statistics2
Calculator
DataQsBeta2
Guides7
PacketSubmit
LoginRegisterTry CY TMS
Violation code

396.7-CDMMNU

Coupling - Semi-Trailer, mismatched coupler/ball/receiver, or not in use, when required

Vehicle Maintenance3Non-OOS· SMS Appendix A v3.20

396.7-CDMMNU is a Coupling Devices violation under 49 CFR §396.7-CDMMNU. It falls in the Vehicle Maintenance BASIC with a severity weight of 3/10. Nationally it was cited 33 times in the last five years, with an OOS rate of 97.0%.

📊

National roadside inspection stats

as of 7/20/2026

Inspections

33

that found this code

Violations

33

total written

OOS rate

97.0%

32 OOS

Source: FMCSA roadside inspection data (last 5 years). The OOS rate is the share of these violations that led the officer to mark the driver or vehicle out of service.

Violation group
Coupling Devices
Regulation §
396.7-CDMMNU
Severity weight
3
Used in SMS
Yes
Status
Active
Updated
7/20/2026

Last updated July 2026

⚡

Think this violation was written incorrectly?

Generate a polished DataQs challenge letter for 396.7-CDMMNU in about 5 seconds. AI quotes the CFR, predicts your grant chance.

⚡ Draft a challenge →

Notes

DSMS: Y | Comment: Added in 3.19
📚

Challenging 396.7-CDMMNU through FMCSA DataQs

If this violation was written incorrectly, here are the angles trucking-safety managers use to contest it. Playbook: Vehicle Maintenance (general).

Common ways to challenge this code

  • Pre-trip inspection showed compliant brakes

    The driver's pre-trip DVIR documented compliant brake adjustment and operation. The cited defect arose en route or was misclassified at roadside.

    Evidence that wins

    • ✓Driver Vehicle Inspection Report (DVIR) from that date
    • ✓Repair invoice or shop record
    • ✓Post-citation re-inspection certificate (clean)

  • Momentary failure exception (§393.9)

    The required lamp was inoperative only momentarily due to vibration, temperature, or similar transient cause — explicitly exempted under §393.9.

    Evidence that wins

    • ✓Photograph showing the lamp operable before / after the stop
    • ✓Repair invoice if a fuse or bulb was replaced

  • Tread measurement disputed

    The tread depth measurement was taken at a worn point that is not representative, contrary to NHTSA/FMCSA measurement standards.

    Evidence that wins

    • ✓Independent tread gauge reading from same tire (multiple positions)
    • ✓Photograph of the tire with a reference scale

  • Documented maintenance schedule disproves the defect

    Carrier's periodic-inspection records show the cited defect could not reasonably have existed at the time of inspection.

    Evidence that wins

    • ✓Periodic inspection certificate (§396.17)
    • ✓Maintenance work order proximate to inspection date

Common pitfalls — avoid these

  • ⚠DataQs cannot remove a violation simply because the defect was repaired after the stop
⚡ Draft a challenge for 396.7-CDMMNU →Read the DataQs guide first

More codes in Vehicle Maintenance

Same BASIC category — ranked by national citation volume

View all Vehicle Maintenance codes →
❓

Frequently asked questions about 396.7-CDMMNU

What does violation 396.7-CDMMNU mean?

396.7-CDMMNU is the FMCSA roadside-inspection violation code for "Coupling - Semi-Trailer, mismatched coupler/ball/receiver, or not in use, when required", part of the Coupling Devices group, cited under 49 CFR §396.7-CDMMNU.

What BASIC does 396.7-CDMMNU affect?

396.7-CDMMNU falls under the Vehicle Maintenance BASIC in the FMCSA Safety Measurement System (SMS).

What is the CSA severity weight of 396.7-CDMMNU?

396.7-CDMMNU carries a severity weight of 3 out of 10. Higher weights indicate violations more closely tied to crash risk, and they count more toward a carrier's Vehicle Maintenance score.

Is 396.7-CDMMNU an out-of-service (OOS) violation?

No. 396.7-CDMMNU is not an out-of-service violation, so on its own it does not trigger an out-of-service order at the roadside.

How many CSA points does 396.7-CDMMNU add to a carrier's score?

The point contribution of 396.7-CDMMNU depends on its severity weight (3/10) multiplied by a time weight of 3, 2, or 1 based on how recent the inspection is. You can calculate the exact contribution with the CSA points calculator.

Can 396.7-CDMMNU be challenged through DataQs?

Yes. If you believe 396.7-CDMMNU was recorded in error, you can file a Request for Data Review (RDR) through the FMCSA DataQs system with supporting evidence. A successful challenge can remove or correct the violation on your record.

Keep going

CSA points calculatorHow to challenge a violationDraft a DataQs letter for 396.7-CDMMNUVehicle Maintenance BASICCarrier CSA lookupCSA glossary
Managing violations across a fleet?

Keep every violation, file, and expiration in one place

Looking up codes one at a time works for research. Running a fleet doesn’t. CY TMS — built by the same safety manager behind VioCodes — puts DQ files, CSA tracking, and compliance reminders in a single system.

$20 / truck / moLive demo · no signup
Explore CY TMS

Field notes & comments

0 comments
Sign in to add a field note.
  • No comments yet — be the first.

Statistics

Most-cited violation codes

Ranked by roadside-inspection citation count across FMCSA public data.