What 393.50C means in plain language
A 393.50C citation means an inspector found your steering mechanism to be defective, broken, or not functioning properly. This covers the entire steering system—the components that let you turn the wheel and control your truck's direction. It's not about minor wear; it's about functionality. If your steering is loose, unresponsive, hard to turn, or shows visible damage to critical parts, you've crossed the line into defective territory.
The steering mechanism is fundamental to safe operation. If it fails while you're driving, you lose control of the vehicle. That's why this violation exists and why inspectors take it seriously at roadside.
What our enforcement data actually shows
Our inspection records show 712 all-time citations for 393.50C, with 447 citations in the last 12 months and 112 in the last 90 days. Importantly, across our 13 million inspections, none of the 712 citations for this code resulted in an out-of-service order—the OOS rate is 0.0%. This is dramatically different from the all-FMCSR average OOS rate of 31.4%, meaning that while inspectors issue citations for steering defects, they typically allow trucks to continue operating after citation.
Ranked #810 out of 3,036 FMCSR codes by citation volume, 393.50C is not among the most frequently cited violations. However, the consistent citation rate—averaging roughly 37 citations per month over the past 12 months—shows it's a recurring issue in the field.
Who gets cited most
Texas dominates the citation count for this code. Our data from the last 180 days shows Texas with 227 citations and a 0.0% out-of-service rate, accounting for a significant share of all 393.50C citations. Because Texas is the only state represented in our top-states list for this violation, the geographic concentration of steering defect citations is narrow, suggesting either higher inspection intensity in that region or a clustering of defective vehicles in cross-border operations.
Our all-time data shows that fleets such as Autolineas America SA de CV have received 10 citations for this code, and Transportes Larmex SA de CV has received 9 citations. Neither pattern suggests systematic negligence; rather, they reflect exposure to high-volume trucking operations and roadside inspection encounters.
How severe is this compared to similar codes
Steering defects are treated as maintenance violations, but their enforcement footprint is small compared to peers. For context, 393.9 (Inoperable Required Lamp) has generated 660,737 citations with a 15.4% OOS rate—roughly 930 times more citations and a much higher enforcement bar for removal from service. Similarly, 393.11 (Lighting devices/reflectors) has 179,734 citations with a 1.8% OOS rate.
The peer code 393.47E (Slack adjuster defective) is instructive: it has 180,363 citations but a 0.0% OOS rate, matching 393.50C's enforcement pattern. This suggests that both steering and brake-adjuster defects are cited frequently but rarely trigger immediate out-of-service action, likely because they are violations inspectors believe can be remedied quickly or because the defect is marginal rather than catastrophic.
How to avoid it
Your pre-trip inspection is your first defense. Steer the truck left and right while parked or at low speed before leaving the lot—feel for binding, excessive play, or resistance. Check the steering column and linkage visually for visible cracks, loose bolts, or bent components. On Freightliner and Kenworth models (which together account for 372 of the 712 all-time citations in our data), pay extra attention to the drag link and tie-rod connections, as these are wear points.
Brake system defects frequently co-occur with steering problems in our inspection data. Over the last 90 days, brake tubing/hose inadequacy (393.45B2UV) appeared in 42 inspections alongside 393.50C citations. This suggests that vehicles with steering issues often have systemic maintenance gaps. Do not skip your brake pre-trip inspection; a comprehensive walk-around catches both.
Worn steering system components (393.53B) co-occurred with 393.50C in 20 inspections over the last 90 days. This tells you that wear is progressive. If you notice steering getting heavier, looser, or noisier over weeks, get it serviced before an inspector does. Fuel system leaks (396.5B) and defective slack adjusters (393.47E) also frequently appear alongside steering citations—all signs that deferred maintenance clusters on the same trucks. Address one defect and inspect for others.
Your fleet manager's preventive maintenance program should schedule steering inspections at regular intervals, not just when you report a problem. The data shows that steering defects are caught consistently at roadside, meaning they exist long enough to be detectable. Early detection in your shop costs far less than a citation, lost hours, and the risk of losing steering control.