What 385.337B means in plain language
385.337B addresses the condition and maintenance of motor vehicle equipment. Specifically, this regulation requires that every commercial motor vehicle be properly equipped and maintained so that all parts and accessories are in good working order and safe condition for operation.
When an inspector cites you for 385.337B, they found something on your vehicle that failed to meet this standard. This could involve mechanical components, structural elements, or equipment that was damaged, missing, or not functioning properly at the time of inspection.
The key point: you're responsible for ensuring your vehicle is roadworthy before you operate it. A 385.337B citation means the inspector determined your vehicle had a defect that violated that requirement.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 385.337B ranks #1166 out of 3,036 FMCSR codes by citation volume. In the last 12 months, we recorded 124 citations nationally for this code. Over the last 90 days, that number was 21 citations.
What makes this code particularly serious: 94.3% of all 385.337B citations result in an out-of-service order. This means inspectors placed the vehicle out of service in 230 out of 244 total cases in our database. For context, the all-FMCSR average out-of-service rate is 31.4%. This code is nearly three times more likely to land a vehicle out of service than the typical FMCSR violation.
If you received this citation, there is a very high probability your vehicle was placed out of service on the spot. That means you could not legally continue operating it until the defect was corrected and the vehicle passed reinspection.
Who gets cited most
Our inspection records show North Carolina leads in 385.337B enforcement over the last 180 days with 17 citations, followed by Texas with 16 citations and Iowa with 9 citations. All three states show extremely high out-of-service rates: North Carolina and Iowa both at 100%, and Texas at 87.5%.
The consistency of these rates across different states indicates this violation is enforced uniformly and results in out-of-service orders regardless of geography.
How severe is this compared to similar codes
Other codes in the General/Admin category show dramatically different enforcement patterns. The code 390.21TB2-DOT has accumulated 74,663 citations but carries a 0.0% out-of-service rate—meaning inspectors almost never place vehicles out of service for it. Similarly, 390.21T(b) has 61,097 citations with 0.0% OOS rate.
Even 390.19B2-BIENNIAL, another administrative code with 16,142 citations, has only a 0.2% out-of-service rate. 385.337B stands in stark contrast: it's cited far less frequently (244 all-time citations), but when cited, it triggers an out-of-service order in nearly every case. This tells you inspectors view equipment defects as serious safety issues that cannot be ignored.
How to avoid it
Our data shows patterns in what co-occurs with 385.337B citations. The most common companion violations involve brake system defects, emergency equipment, lighting, and vehicle maintenance records. Here's what you can do:
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Perform a thorough pre-trip inspection every time you operate. Check all lights (headlights, taillights, turn signals, marker lights), test your brakes by applying steady pressure before leaving the lot, and visually inspect hoses, belts, and fluid levels. Freightliner trucks (FRHT) represent 64 of our 385.337B citations—these vehicles warrant extra attention to air brake systems and air lines.
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Verify your emergency equipment is present and functional: fire extinguisher mounted and accessible, spare fuses available, warning triangles or flares in the cab. This equipment co-occurs with 385.337B violations in our data with high frequency.
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Maintain proof of periodic inspections. Our data shows 396.17C (no proof of periodic inspection) appears together with 385.337B in 6 shared inspections over 90 days. Keep your vehicle maintenance records current and accessible.
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Do not operate if you are ill or fatigued. Violations 392.2RG and 392.2 co-occur with 385.337B, suggesting that impaired judgment may lead to operating unsafe equipment. A safe vehicle starts with a safe driver.
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Know your vehicle's critical systems before you drive. If you operate a Ford (31 citations in our data), International (22), Ram (21), or Kenworth (20), familiarize yourself with that model's common weak points. Talk to your maintenance team about what to watch for.
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If you receive an out-of-service order, do not drive. With a 94.3% OOS rate on this code, you will almost certainly be placed out of service. Driving a vehicle ordered out of service carries additional federal penalties and can result in fines for both you and your carrier.
The bottom line: 385.337B violations are rare compared to other FMCSR codes, but when they occur, they are treated as serious equipment safety defects. The data shows inspectors view these violations as non-negotiable. Your best defense is a rigorous, consistent pre-trip inspection routine and immediate corrective action if you identify any defect.