What 393.45D-BHTBS means in plain language
Your citation for 393.45D-BHTBS means an inspector found that your brake tubing or hoses are worn, chafed, crimped, or otherwise damaged. Brake tubing and hoses carry pressurized fluid that stops your truck. When they're damaged, that system loses integrity.
Damage can take several forms. Chafing occurs when tubing rubs against frame, engine components, or sharp edges—friction wears through the outer layer and eventually compromises the tube wall. Crimping happens when tubing gets bent sharply, restricting or blocking fluid flow. Wear appears as surface degradation, thinning walls, or corrosion. Any of these reduces your brakes' ability to function reliably and increases the risk of sudden pressure loss during operation.
Inspectors check brake lines during roadside inspections by looking at routing, condition, and attachment points. They're looking for signs that the system won't hold pressure or could fail under braking demand.
What our enforcement data actually shows
Our inspection records show that 393.45D-BHTBS is a relatively uncommon citation. Across 13 million+ inspections in our database, this code has generated only 1 citation all-time and 1 citation in the last 12 months. In the last 90 days, we've recorded 1 citation.
When this code is cited, the out-of-service rate is exceptionally high. The 1 citation on record resulted in an out-of-service determination, yielding a 100.0% OOS rate. For context, the all-FMCSR average out-of-service rate is 31.4%, so a brake-tubing defect, when found, is treated as a serious enough issue to ground the vehicle immediately in 100% of cases in our data.
This code is ranked #2796 of 3,036 FMCSR codes by citation volume nationally, placing it well below the median in enforcement frequency.
Who gets cited most
Georgia accounts for 1 citation of this code in the last 180 days, with 1 out-of-service placement (100.0% OOS rate).
Our data shows fleets such as APAC LOGISTICS LLC (USDOT 4281195) with 1 citation all-time for this violation.
Because citation volume is very low, state-by-state and carrier-by-carrier variation is minimal in our records.
How severe is this compared to similar codes
Brake and lighting codes fall into the same vehicle-maintenance category. Here's how 393.45D-BHTBS compares:
393.9(a) — Inoperable required lamps has 660,737 citations all-time with a 15.4% OOS rate. That code is far more common but results in out-of-service placement much less frequently.
396.3(a)(1) — Inspection/repair/maintenance general generated 236,919 citations all-time with a 45.3% OOS rate. This is a broader maintenance code that's cited more often and removed from service more frequently than inoperable lamps.
393.47E — Slack adjuster defective produced 180,363 citations all-time with a 0.0% OOS rate. Despite being a brake-related code, slack-adjuster defects are cited much more often than brake-tubing damage but rarely result in out-of-service orders.
The 100.0% OOS rate on 393.45D-BHTBS reflects the critical safety role of brake-system integrity. Unlike a failed lamp or a slack adjuster that may be borderline, a damaged brake tube is treated as an immediate hazard.
How to avoid it
Prevent a 393.45D-BHTBS citation with these concrete pre-trip actions:
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Trace brake lines during your walk-around inspection. Follow the routing from the master cylinder through the ABS module and down to each wheel. Look for lines that rub against sharp edges, engine components, or the frame. If you spot a line touching metal, it needs repositioning or wrapping before it wears through.
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Check for visible damage every time you do a pre-trip. Run your hand gently along tubing and hoses (when the system is not pressurized). Feel for soft spots, blisters, cracks, or areas where the outer covering is missing. Chafing often starts on the underside of a line where you can't see it immediately—check underneath and at tight bend points.
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Replace or repair any tubing showing wear or discoloration immediately. Don't wait until the next scheduled maintenance. Brake fluid is corrosive and can degrade tubing from the inside out. Any visible thinning, flaking paint, or rust-colored staining is a red flag.
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Secure loose tubing with clips and clamps. Tubing that vibrates or moves during operation will eventually chafe. Make sure every line is held in place by factory clips or securely fastened clamps spaced appropriately along its length.
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Inspect hose connections and fittings for leaks. A small drip from a fitting can indicate internal pressure loss or a weak seal. Tighten fittings if they're loose, and replace hoses if they're weeping.
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Pay attention to co-occurring maintenance issues. Our data shows that when this code appears, it often shows up alongside other vehicle and equipment defects. If you're addressing one brake issue, perform a full brake-system walk-around, including emergency equipment and lighting, to catch and fix related problems before they become citations.