What 393.50B-B means in plain language
When you receive a citation for 393.50B-B, the inspector found that your steering mechanism is defective, broken, or not functioning properly. This isn't a minor wear issue—steering is a safety-critical system. A steering mechanism that doesn't work reliably means you can't control your vehicle predictably, which puts you, other drivers, and cargo at immediate risk.
The steering mechanism includes the steering wheel, column, gearbox, tie rods, drag links, and all connecting components that translate your hand movements at the wheel into direction changes. If any part is cracked, bent, has excessive play, is loose, or isn't responsive, it can be cited under this code. Inspectors test for smooth operation, proper alignment, and absence of physical damage or wear that compromises control.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.50B-B is a low-frequency violation, with 10 all-time citations. However, it carries serious weight: 80% of citations result in an out-of-service order—that means you cannot legally operate the vehicle until the defect is fixed. This is significantly higher than the all-FMCSR average out-of-service rate of 31.4%.
In the past 12 months, we've recorded 6 citations for this code, with 2 occurring in the last 90 days. The low volume reflects that most fleets catch steering defects during routine maintenance. When they slip through, the consequence is almost certain: of the 10 all-time citations, 8 resulted in out-of-service placement and only 2 did not.
Who gets cited most
Over the last 180 days, citations for 393.50B-B have been concentrated in three states: Florida (1 citation, 100% OOS rate), Georgia (1 citation, 100% OOS rate), and Montana (1 citation, 100% OOS rate). All three resulted in immediate out-of-service orders. Our data shows individual operators and smaller fleets receiving citations, including carriers such as Swift Transportation Co of Arizona LLC and Corney Transportation Inc, each with 1 citation on record. The small sample size means regional and carrier-level patterns are not yet conclusive, but the out-of-service rate remains consistently high.
How severe is this compared to similar codes
Steering defects are treated far more seriously than many other vehicle maintenance violations. For comparison, inoperable required lamps (393.9(a)) has generated 660,737 citations with only a 15.4% out-of-service rate. Inspection, repair, and maintenance violations in general (396.3(a)(1)) show 236,919 citations with a 45.3% out-of-service rate. Windshield condition defects (393.78) have 157,894 citations but only a 0.3% out-of-service rate.
The 80% out-of-service rate for steering defects underscores that regulators view a broken steering system as an immediate hazard that cannot be remedied while the vehicle remains in service. Steering functionality is non-negotiable; you cannot operate around it.
How to avoid it
Steering defects are preventable with disciplined pre-trip and periodic maintenance:
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Check steering play at every pre-trip inspection. Grasp the steering wheel at 9 and 3 o'clock with the engine off and wheels straight. Rotate gently—there should be minimal free play (typically less than 2 inches of wheel rotation before the front wheels move). Excessive play signals wear in the gearbox, column, or tie rods.
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Visually inspect all visible steering components. Look under the vehicle for bent or cracked tie rods, drag links, and pitman arms. Check for torn boots on the steering gearbox. Inspect the steering column where it enters the cab for cracks or deformation.
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Test steering responsiveness during slow movement. In a safe area, move forward slowly and turn the wheel smoothly in both directions. The vehicle should respond immediately and predictably. Any lag, binding, or unusual resistance is a red flag.
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Monitor for signs of hydraulic steering leaks. If your truck has power steering, look for fluid on the undercarriage, in the engine bay near the pump, or around hose connections. Low fluid or leaks will degrade steering function progressively.
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Have steering geometry checked periodically. Our data shows that Wabash National and International vehicles appear in the citation history. Regardless of make, worn front-end components (ball joints, kingpins, bearings) can manifest as steering problems. Schedule alignment and front-end checks as part of scheduled maintenance.
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Pay attention to co-occurring defects. Our inspection records show that steering citations frequently occur alongside brake defects (particularly brake out-of-service violations and inoperative brakes) and tire issues. If you're cited for one, conduct a comprehensive inspection of all three systems—they interact, and one failure often masks or accelerates another.
The 80% out-of-service rate for this violation means that if you're cited, your truck is likely going off the road immediately. The cost of an emergency repair at a roadside facility, plus lost revenue and delay, far exceeds the cost of proactive maintenance. Steering is your primary control system—treat it that way.