FMCSA Violation Code

393.40 — Required brakes inoperative

49 CFR 393 • Vehicle Maintenance BASIC • Severity 4/10

Out-of-service eligible Vehicle citation CSA weight 4

OUT-OF-SERVICE eligible

Code

393.40

CFR section

49 CFR 393

BASIC

Vehicle Maintenance

Severity

4/10

Out-of-Service

Yes

Unit type

Vehicle

What this violation means

Service brakes, parking brakes, or emergency brakes inoperative on a required wheel. OOS. Different from individual-wheel adjustment violations — this covers complete brake system loss.

Why this gets cited

Severed brake line. Failed compressor. Frozen brake.

How to fix / prevent

Don't drive. Repair before operating.

Out-of-service criteria

Yes — this violation IS out-of-service eligible. When an inspector finds 393.40 during a Level 1, 2, or 3 inspection, they can place the Vehicle OOS using the North American Standard Out-of-Service Criteria. OOS means the truck cannot move from the inspection site until the defect is corrected (vehicle OOS) or the driver is replaced (driver OOS). For carriers, every OOS violation adds time-weighted points to your CSA Vehicle Maintenance BASIC — and it shows in the public SMS data within 30 days. For drivers, an OOS event stays on PSP for 3 years.

CSA / SMS impact

393.40 carries a severity weight of 4/10 in FMCSA's Safety Measurement System (SMS). Higher weights mean faster CSA percentile movement. Combined with a time-weighting factor (2× for citations within the last 6 months, decaying over 24 months), this violation can move your Vehicle Maintenance BASIC percentile significantly if it stacks with similar citations across your fleet. The threshold for FMCSA intervention is the 65th percentile for most BASICs (50th for Hazmat and Passenger Carrier). Once you cross that, FMCSA can send a Warning Letter, Off-Site Investigation, or full Compliance Review.

How to read this: a single citation rarely puts you over threshold — it's the pattern. Track your inspection rate per power unit and aim for OOS rate under 5% (industry average is 21%).

Carriers recently cited (last 24 months)

Carriers most-recently cited for 393.40 in FMCSA inspection records (rolling 24-month window).

MORELLI LOGISTICS LLC
DOT #3439211 • last cited 2024-10-02
6×
TWIN PEAKS TREE SERVICE LLC
DOT #2323809 • last cited 2024-11-27
5×
MTB LANDSCAPING LLC
DOT #4104642 • last cited 2024-11-27
5×
LEGION LOGISTICS INC
DOT #3625172 • last cited 2025-06-27
4×
MARYLAND TREE EXPERTS
DOT #3304931 • last cited 2025-04-16
4×
J A PROPERTY FENCING INC
DOT #4173413 • last cited 2025-03-19
4×
CAPPELLI PROPERTY SERVICES LLC
DOT #3553096 • last cited 2024-11-13
4×
WATSON CONTRACTING
DOT #2424639 • last cited 2024-09-04
4×
TINARI CONTRACTORS INC
DOT #381998 • last cited 2024-09-04
4×
PRO CONSTRUCTION TEAM LLC
DOT #1083989 • last cited 2024-08-30
4×

Other violations in Vehicle Maintenance

396.9C2OOS

Operating vehicle declared out-of-service

393.75AOOS

Flat tire or audible air leak

393.75A1OOS

Tire ply or belt material exposed

393.75A3OOS

Tire with fabric exposed

393.75FOOS

Tire on steering axle under 4/32 inch tread

393.75GOOS

Tire on non-steering axle under 2/32 inch tread

393.83A2OOS

Exhaust discharges into cab/sleeper

393.5AOOS

Coupling device defective (fifth wheel, pintle, kingpin)

Frequently Asked Questions

Can I be placed out of service for 393.40?

Yes. 393.40 is on the North American Standard Out-of-Service Criteria list. An inspector who finds this during a Level 1, 2, or 3 inspection can place the Vehicle OOS at the inspection site. The truck cannot move until the defect is corrected. For vehicle-side OOS, that usually means a mobile mechanic or tow to the nearest shop. For driver-side OOS (HOS, CDL, drug/alcohol), it means the driver is removed from service and a qualified replacement must arrive before the truck can continue. Pro tip: do a thorough pre-trip every shift and address any issue listed in 49 CFR 393 before pulling onto the road — that's the only reliable way to avoid this one.

How long does 393.40 affect my CSA score?

393.40 stays in your CSA Vehicle Maintenance BASIC for 24 months from the inspection date. The impact is time-weighted: 3× points during months 0-6, 2× during months 7-12, 1× during months 13-24, then it drops off. Severity weight is 4/10, so each citation contributes 12 points in the first 6 months and decays from there. On the driver's PSP report, the same citation stays visible for 36 months — and a 5-year history of driver violations is available to motor carriers performing a hire review. If the citation is later dismissed in court (DataQs challenge succeeds, or the underlying ticket is dropped), the SMS record can be removed via FMCSA's DataQs portal — but you have to actively file the challenge.

Can I fight a 393.40 citation?

Yes, and you should consider it. FMCSA's DataQs system at dataqs.fmcsa.dot.gov lets carriers (and drivers) challenge any inspection violation. The two strongest grounds are: (1) the underlying state citation was dismissed or reduced in court — submit court paperwork as evidence; (2) the inspector applied the wrong code — for example, citing 393.40 when the correct citation is a different code with lower severity. DataQs has roughly a 35-40% reversal rate when carriers submit clean court documentation. The catch: you have to file within 24 months of the inspection, and the inspector's narrative usually wins ties. Because this is an OOS-eligible violation, the SMS impact is significant — even a successful DataQs reversal is worth it. Budget 2-4 hours per challenge plus any legal cost.

Does 393.40 show on PSP (Pre-Employment Screening)?

No — 393.40 is a vehicle-side violation, so it shows on the CARRIER's CSA scores (via the SMS public website) but NOT on the driver's individual PSP record. PSP only reports inspections where the driver received a citation. Vehicle defects discovered during the same inspection don't follow the driver. This matters: if you're a driver inspected on a truck with vehicle violations you weren't responsible for (faulty company equipment), those don't follow you to your next job.

What's the difference between 393.40 and similar codes?

393.40 is in the 8-code group sharing the same BASIC. The closest siblings are: 396.9C2 (Operating vehicle declared out-of-service); 393.75A (Flat tire or audible air leak); 393.75A1 (Tire ply or belt material exposed). Inspectors often cite multiple sibling codes from the same inspection — for example, a tire condition violation can simultaneously trigger codes for tread depth, sidewall, and inflation pressure. When you get cited under one sibling, check the report for the others before signing — they all count separately against CSA scoring.

How do I prevent 393.40 from getting cited again?

Don't drive. Repair before operating.

CSA scores rising? Get a compliance audit.

(682) 978-8641 Send a message

393.40 — Required brakes inoperative

What this violation means

Related

Frequently Asked Questions

CSA scores rising? Get a compliance audit.

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