What 393.50 means in plain language
FMCSR 393.50 flags a steering mechanism that is defective, broken, or not functioning properly on your commercial motor vehicle. This isn't a minor wear issue—it's a safety failure in the core system that lets you control the truck's direction.
The steering mechanism includes the steering wheel, steering column, gearbox, linkage rods, tie-rods, and all connected components that translate your input into wheel movement. If an inspector finds cracks, binding, excessive play, bent components, or any condition that prevents smooth or reliable steering, they can cite you under this code.
A defective steering system can make a truck impossible to control in an emergency or lead to unintended lane changes. That's why this violation can result in an out-of-service order, preventing you from operating the vehicle until repairs are made.
What our enforcement data actually shows
Across 13 million inspections in our database, 393.50 has been cited 464 times all-time, with 97 citations in the last 12 months and 19 in the last 90 days. This code ranks #949 of 3,036 FMCSR codes by citation volume, making it relatively uncommon in the broader enforcement landscape.
However, the out-of-service rate tells a different story about severity. Our inspection records show an 18.3% OOS rate for 393.50—meaning roughly 1 in 5 citations result in the truck being pulled out of service immediately. This is notably lower than the all-FMCSR average OOS rate of 31.4%, suggesting that inspectors have some discretion in how they handle steering defects, or that defects vary in severity.
Looking at recent trends, our data indicates a relatively stable enforcement pattern over the last 12 months, with monthly citations ranging from 2 to 14. June 2025 saw a spike to 14 citations, and October 2025 reached 11—both higher than surrounding months—but there's no clear escalating trend.
Who gets cited most
Texas leads enforcement activity, with 40 citations over the last 180 days and a 10.0% OOS rate. New Mexico follows with 3 citations but a higher 33.3% OOS rate, and North Carolina has 1 citation with a 0.0% OOS rate.
The variation in OOS rates across states is notable: New Mexico's 33.3% rate is more than triple Texas's 10.0% rate. This could reflect differences in inspector discretion, the severity of defects encountered, or repair availability in those regions. Texas's lower OOS rate despite higher citation volume suggests many steering issues there are being cited but resolved without immediate vehicle removal.
Our data shows the carriers cited most frequently include JULIO CESAR CIENFUEGOS GARZA with 6 citations and XPRESS INTERNACIONAL S DE RL DE CV with 4 citations. This pattern alone does not indicate negligence but does highlight which fleets have encountered steering defects during roadside inspections.
How severe is this compared to similar codes
393.50 sits in the Vehicle Maintenance category alongside dozens of other mechanical violations. Comparing it to related codes reveals its relative standing:
- 393.9(a) — Inoperable required lamps has been cited 660,737 times with a 15.4% OOS rate. Lighting defects are far more common but slightly less likely to result in immediate out-of-service action.
- 396.3(a)(1) — Inspection/repair/maintenance general shows 236,919 citations and a 45.3% OOS rate—this broader maintenance code is cited more than 500 times as often as 393.50 and results in out-of-service placement nearly 2.5 times more frequently.
- 393.11 — Lighting devices/reflectors has 179,734 citations with only a 1.8% OOS rate, indicating minor lighting defects are rarely severe enough for immediate removal.
By this comparison, steering defects are less frequently cited than lighting or general maintenance violations but carry a more serious consequence when they are found. The 18.3% OOS rate reflects that steering integrity is genuinely hazardous.
How to avoid it
Your pre-trip inspection is your first line of defense. Steering defects don't usually appear overnight, and a methodical walk-around can catch problems before an inspector does.
Steering-specific checks:
- Check for play in the steering wheel. Grasp the steering wheel at 3 and 9 o'clock and try to move it up and down without turning the engine on. Any clunking, grinding, or excessive movement signals wear or damage in the column or gearbox.
- Turn the wheel lock-to-lock. Slowly rotate the steering wheel from full left to full right while parked. It should move smoothly without binding, catching, or grinding sounds. Any resistance or noise warrants investigation.
- Inspect visible linkage and tie-rods. Look under the vehicle for bent, cracked, or severely worn components. Pay special attention to the tie-rods and steering arms where they connect to the wheels.
- Check for fluid leaks under the steering column or power-steering reservoir. A power-steering fluid leak can cause steering to become stiff or unresponsive.
Broader maintenance discipline:
Our enforcement data shows that steering defects often co-occur with other maintenance issues. In the last 90 days, 393.50 appeared alongside slack adjuster defects (code 393.47E) in 3 shared inspections and brake chamber failures (393.47A) in 2 shared inspections. This pattern suggests that trucks cited for steering problems often have multiple deferred maintenance items. Implement a comprehensive pre-trip routine that includes brake adjusters, suspension, and lighting alongside steering checks.
Vehicle make data shows FRHT (Freightliner) trucks account for 59 of the 464 all-time citations for this code, followed by INTL (International) with 36 and KW (Kenworth) with 35. If you operate one of these common makes, research steering issues specific to your model year and watch for early warning signs.
Finally, don't ignore the first sign of steering trouble—a pull to one side, delayed response, or a clunking sound. Small defects grow into dangerous ones, and a brief repair stop is far cheaper and safer than a roadside citation and out-of-service order.