What 393.207G means in plain language
FMCSR 393.207G requires that air suspension exhaust control systems on your truck be functional and in good working order. The air suspension exhaust control is the mechanism that vents compressed air from your suspension system safely and properly. When this system is missing, broken, or not working as designed, you are in violation of this code.
This defect can range from a loose or missing exhaust line to a valve that no longer seals or directs air correctly. The regulation is straightforward: if your air suspension has an exhaust control component, it must be present and operational. Inspectors check this during roadside inspections by visually examining the suspension system and its venting apparatus.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.207G has been cited 102 times all-time, with 64 citations in the last 12 months and 12 in the last 90 days. This ranks the code at #1413 of 3,036 FMCSR codes by citation volume, making it a relatively infrequent violation.
What matters most for your situation: only 2 out of 102 citations resulted in an out-of-service order, yielding a 2.0% OOS rate. For context, the all-FMCSR average OOS rate is 31.4%. This means that when officers cite 393.207G, they almost always allow you to continue operating—it is not treated as an immediate safety-critical defect in the vast majority of cases.
The monthly trend shows the highest citation volume occurred in July 2025 with 10 citations, and January 2026 with 10 citations and 1 OOS. Most months see between 2 and 8 citations.
Who gets cited most
Our inspection records show citations concentrated in a small number of states. Texas leads with 29 citations and a 0.0% OOS rate over the last 180 days, suggesting inspectors there cite the defect but do not view it as grounds for immediate removal from service. North Carolina had 1 citation in the same period, and that single case resulted in an OOS order (100.0% rate), though this sample size is too small to draw broad conclusions.
Among carriers, our data shows fleets such as Julio Cesar Cienfuegos Garza (USDOT 2389566) with 3 all-time citations, and several carriers with 2 citations each, including Florencio Garcia Ruvalcaba (USDOT 909856) and Especializados en Estructuras Metalicas Lober SA de CV (USDOT 557463). These counts are modest and do not indicate systemic non-compliance within any particular fleet.
How severe is this compared to similar codes
In the Vehicle Maintenance category, 393.207G sits well below many peer violations in terms of citation frequency and enforcement severity. For comparison:
- 393.9(a) — Inoperable required lamps has 660,737 citations with a 15.4% OOS rate. This code is cited nearly 6,500 times more frequently.
- 396.3(a)(1) — Inspection/repair/maintenance (general) has 236,919 citations and a 45.3% OOS rate, meaning inspectors remove trucks for this violation nearly 2,300 times more often than for 393.207G.
- 393.47E — Slack adjuster defective has 180,363 citations but a 0.0% OOS rate, similar to 393.207G in that it rarely triggers out-of-service status despite high citation volume.
The low OOS rate for 393.207G indicates regulators treat this as a maintenance item rather than an acute safety hazard.
How to avoid it
Our inspection data reveals patterns in what defects commonly occur alongside 393.207G citations. Inspectors finding air suspension exhaust control problems also frequently note brake and suspension system defects on the same truck. Here is how to prevent this citation:
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Inspect your air suspension system weekly. Walk around your truck and visually trace the air suspension plumbing. Look for the exhaust line or vent port on your suspension system. Ensure it is present, not loose, and not kinked or blocked. This takes less than two minutes.
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Check for cracks or separation in the exhaust line. Air suspension exhaust lines can crack due to vibration and age. If you see any splits, disconnected fittings, or deterioration in the rubber or metal tubing, schedule repairs immediately.
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Listen for unusual hissing or air leaks during operation. A failing exhaust control may leak air continuously. If you hear sustained hissing from the suspension area while the truck is running, have the system diagnosed before your next inspection.
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Pay attention to brake and steering systems at the same time. Our data shows that 393.47E (slack adjuster defects) and 393.53B (steering system wear) frequently appear on the same trucks as 393.207G violations. A thorough weekly walk-around will catch all three categories.
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Verify your truck model's specific location for this component. Freightliner (FRHT) trucks account for 29 of the 102 citations in our database, followed by Kenworth (KW) with 14 and Volvo (VOLV) with 11. If you drive one of these makes, consult your owner's manual to confirm where the air suspension exhaust control is located and what it should look like when intact.
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Address fuel system and brake tubing issues promptly. Citations for 396.5B (fuel system leaks) and 393.45B2UV (brake tubing inadequacy) co-occur with 393.207G defects in our data, suggesting general neglect of system integrity inspections. A preventive maintenance mindset will reduce your risk across all three.
The citation you received is not severe by enforcement standards, but it does indicate an inspection found a part that needs attention. Address it before your next roadside check to avoid a repeat citation or a future OOS order.