What 393.50A means in plain language
A 393.50A citation means an inspector found that your truck's steering mechanism is defective, broken, or not functioning properly. This covers the entire steering system—the components and connections that let you control the direction of the vehicle.
Steering defects can range from loose components and worn joints to hydraulic failures, damaged tie rods, or a steering wheel that doesn't respond correctly. The regulation exists because a steering failure at highway speed creates an immediate hazard to you, your cargo, and everyone else on the road.
Unlike some mechanical violations, 393.50A is not an automatic out-of-service citation. That means the inspector has discretion based on severity. A minor issue might be written up as a violation you can fix within a timeframe; a critical steering failure may result in immediate removal from service.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.50A is a low-frequency violation. We've recorded 8 all-time citations for defective steering mechanisms, with 3 citations in the last 12 months and 0 in the last 90 days. This code ranks #2269 out of 3,036 FMCSR codes by citation volume.
When inspectors do cite 393.50A, the severity shows up in the out-of-service rate: 62.5% of the 8 citations resulted in an OOS order. That's double the all-FMCSR average OOS rate of 31.4%, indicating that when steering defects are caught, they tend to be serious enough to ground the vehicle immediately.
In the most recent data window (last 12 months), we saw 3 total citations with a monthly spike of 2 citations and 2 OOS orders in May 2025, followed by 1 citation with no OOS in January 2026.
Who gets cited most
Our inspection records show that in the last 180 days, Texas accounted for 1 citation with a 0.0% OOS rate—meaning that one Texas citation did not result in an out-of-service order.
All-time, the citations are distributed across small carriers and independent operators. Our data shows fleets such as Synagro Central LLC, Ean Holdings LLC, and Maldonado Trucking Group LLC each with 1 citation in the database. No single carrier dominates this violation category, which reflects the rarity of the citation and the fact that steering defects are typically caught through routine pre-trip inspection or driver reporting rather than systemic fleet negligence.
How severe is this compared to similar codes
Steering is a critical safety system, and 393.50A sits in the Vehicle Maintenance category alongside dozens of other mechanical violations. To put this in context:
Inoperable required lamps (393.9a) is by far the most common citation in this category, with 660,737 all-time citations but only a 15.4% OOS rate. Steering defects, by contrast, are cited far less often but are grounded nearly four times as frequently.
General inspection/repair/maintenance (396.3a1) shows 236,919 citations with a 45.3% OOS rate, reflecting the broad nature of that violation. Slack adjuster defective (393.47E) has 180,363 citations with a 0.0% OOS rate, indicating that brake slack adjusters are typically corrected without immediate removal from service.
The high OOS rate on 393.50A (62.5%) tells you that inspectors view steering defects as non-negotiable safety issues that warrant immediate action.
How to avoid it
Steering requires pre-trip vigilance and preventive maintenance discipline:
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Perform a full steering check at every pre-trip inspection. Turn the wheel lock-to-left and lock-to-right before moving the truck. Feel for binding, excessive play, or grinding. Any dead zones or delay in response is a red flag.
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Check the steering wheel itself. Excessive play (more than a couple of inches of movement before the wheels respond) indicates wear in the steering column, gearbox, or linkage. This is one of the easiest checks to do and one inspectors always look for.
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Inspect steering column connections and U-joints. These joints and fasteners wear and can develop play or cracking. Look for any visible cracks, rust buildup suggesting movement, or loose bolts. Tighten or replace as needed.
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Test your power steering system if equipped. Listen for whining (sign of low fluid or pump wear) and feel for resistance when turning at a standstill. Low power steering fluid is a common culprit and a fast fix.
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Check tie rod ends and ball joints. These wear out and develop play over time. Grasp the tire at 3 and 9 o'clock and try to move it. Any clicking or clunking when you do, or play at the wheel rim, signals worn steering linkage. This requires shop attention.
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Keep your maintenance records current. If you have steering work done—fluid changes, component replacement, alignment—document it. An inspector may ask.
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Don't ignore early warning signs. If you notice the truck pulling to one side, the steering wheel vibrating, or feeling loose or slow to respond, report it to your fleet immediately and have it diagnosed before you're back on the road. Waiting until roadside inspection is how 393.50A citations happen.