FMCSR 393.41 – No or Defective Parking Brake: Driver FAQ

Almost certainly yes. Across 11,285 all-time citations in our inspection records, 393.41 carries a 94.7% out-of-service rate—meaning 10,689 of those inspections ended with the vehicle parked until repaired. For context, the all-FMCSR average OOS rate is only 31.4%, so this code runs nearly three times higher than typical. In the last 180 days, every state where enforcement is concentrated shows similar numbers: Texas hit 95.5%, Illinois 97.5%, and New Mexico reached 100.0%. If an inspector finds no working parking brake, assume you are not driving away.

The STATISTICS block for 393.41 does not include a severity weight value, so a precise point total cannot be stated here. What the data does confirm is that 393.41 is ranked #212 out of 3,036 FMCSR codes by citation volume, placing it well inside the top 10% of all cited codes. Because it falls under the Vehicle Maintenance BASIC, citations attach to both the driver's PSP record and the carrier's BASIC score. A violation cited within the last 6 months carries the full weight; it steps down at the 12- and 24-month marks under FMCSA's time-weighting rules.

Stop operating the vehicle until the parking brake is repaired and documented. With a 94.7% OOS rate, the inspector has very likely already grounded the truck. Immediate steps:

1. Get the brake repaired by a qualified mechanic and obtain a signed repair order.
2. Check for companion violations. Our inspection records show that in the last 90 days, 393.41 appeared alongside inoperable required lamps (393.9, 51 shared inspections), missing fire extinguishers (393.95A, 47 shared inspections), and no proof of periodic inspection (396.17C, 42 shared inspections). Address all of them before returning to service.
3. Notify your safety manager so the carrier's BASIC score can be monitored.
4. Keep all repair paperwork—you'll need it if you file a DataQs challenge.

Yes—it's one of the most serious by OOS rate in its category. Our database shows peer Vehicle Maintenance codes far below 393.41's 94.7% rate: inoperable required lamps (393.9) sits at 6.9%, windshield defects (393.78) at 0.3%, and even the general inspection/maintenance code (396.3(a)(1)) comes in at 45.3%. The all-FMCSR average is 31.4%. A defective parking brake is treated by inspectors as an immediate safety threat, not a paperwork issue, which is why the OOS response is so consistent and so much higher than nearly every comparable code.

Yes, you can submit a Request for Data Review (RDR) through FMCSA's DataQs system. Because 393.41 is an equipment defect finding—not a documentation violation—a successful challenge typically requires proof that the condition either did not exist at the time of inspection or was recorded in error. Useful evidence includes a pre-trip inspection log showing the brake was tested and functional, a mechanic's inspection report dated before or on the citation date, or photos. Documentation-only violations are harder to contest; equipment findings like this one require physical proof. Filing does not automatically remove the citation, but a sustained challenge will clear it from both your PSP and the carrier's BASIC.

Texas, Iowa, and Illinois top the list. In the last 180 days, our inspection records show Texas with 178 citations (95.5% OOS rate), Iowa with 62 citations (93.5% OOS rate), and Illinois with 40 citations (97.5% OOS rate). North Carolina added 13 citations and New Mexico 9, with New Mexico placing every single cited vehicle out of service (100.0%). If your routes run through any of these states—especially Texas—parking brake condition should be a pre-trip priority, not an afterthought.

It cannot wait. A 94.7% OOS rate means inspectors treat a missing or defective parking brake as a condition requiring immediate grounding. Beyond the regulatory reality, our records show enforcement volume is not fading: the last 12 months logged 799 citations, with July 2025 alone hitting 92 citations (87 OOS). Monthly totals have stayed in the 58–92 range for most of the trailing year. Deferring repair to a scheduled PM interval means operating a vehicle that will almost certainly be placed out of service the moment an inspector sees it, adding downtime and a citation on top of the original defect.

Both. Under FMCSA's CSA methodology, a vehicle maintenance violation like 393.41 is assigned to the carrier's Vehicle Maintenance BASIC because the carrier is responsible for keeping equipment roadworthy. At the same time, the citation appears on the driver's PSP (Pre-Employment Screening Program) record, which prospective employers can review. Our database lists Federal Express Corporation (USDOT 86876) with 98 all-time citations and United Parcel Service Inc (USDOT 21800) with 35, illustrating that even large, structured fleets accumulate carrier-side exposure. Drivers who rack up equipment violations across multiple carriers will see that pattern follow them on their PSP regardless of which carrier owned the truck.