What 393.201B-FR means in plain language
This violation comes down to the physical connection between your cab or body and the vehicle frame. Those mounts — the brackets, bolts, cushions, and hardware that hold the cab or body structure securely to the frame — are required to be intact, tight, and present. If an inspector finds that any of them are loose, fractured, or outright missing, you get cited under 393.201B-FR.
It sounds like a minor structural detail, but the mounts do real work. They absorb road vibration, keep the cab aligned over the frame, and prevent dangerous movement under load or during maneuvering. A missing or broken mount doesn't just affect ride quality — it can allow progressive structural shift that worsens with every mile driven.
The citation applies to the front cab mounts as well as the rear body mounts depending on the vehicle configuration. Inspectors look for visible cracking at the mount points, hardware that has backed out or sheared off, and rubber isolators that have deteriorated to the point where metal-to-metal contact is occurring or the mount is functionally gone.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.201B-FR has generated 6,757 all-time citations, placing it at #290 out of 3,036 FMCSR codes by citation volume — well inside the top 10% of all codes enforced. That's not a rare or obscure violation; inspectors cite it regularly and know what to look for.
The out-of-service picture is notably driver-friendly. Of those 6,757 citations, only 47 resulted in an OOS order — a rate of just 0.7%. To put that in context, the all-FMCSR average OOS rate across every code in our database is 31.4%. Getting cited for 393.201B-FR does not typically mean your truck gets parked on the spot, but it absolutely goes on your inspection record and feeds into your carrier's SMS scores.
Enforcement activity is accelerating. Our inspection records show 4,345 citations in the last 12 months alone, meaning that period accounts for more than 64% of all all-time citations for this code. In just the last 90 days, inspectors issued 907 citations — a pace that makes this one of the more actively enforced structural codes on the books right now. Monthly volumes from our database peaked at 489 citations in August 2025 and have remained above 300 most months since, with December 2025 standing out as the month with the highest OOS count at 8 orders.
Who gets cited most
Looking at the last 180 days of our inspection data, California leads all states by a wide margin with 501 citations and a 1.4% OOS rate. New Jersey is second with 241 citations, and New York third with 192 citations — both at a 0.0% OOS rate. The gap between California's OOS rate and those two states is relatively small in absolute terms, but California is the only top state where inspectors are placing vehicles out of service for this code with any regularity.
Other states appearing prominently in our data include Pennsylvania (72 citations), Georgia (71 citations), Maryland (63 citations), Connecticut (62 citations), and Washington (62 citations). The concentration in the Northeast corridor — New Jersey, New York, Pennsylvania, Maryland, Connecticut — suggests that port, urban delivery, and regional distribution operations face particular exposure here.
Among carriers, our data shows fleets such as HOME EXPRESS DELIVERY SERVICE LLC (USDOT 2714701) with 19 citations and SOUTHERN GLAZER'S WINE AND SPIRITS LLC (USDOT 420647) with 18 citations leading all-time counts. Both are high-cycle delivery operations, which reflects the wear patterns this violation tends to follow.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 393.201B-FR is modest in volume but worth comparing to some of the heavyweights around it. 393.9(a) — Inoperable required lamps has been cited 660,737 times in our database with a 15.4% OOS rate — nearly 100 times the citation volume of 393.201B-FR and an OOS rate roughly 22 times higher. 396.3(a)(1) — Inspection/repair/maintenance (general) carries 236,919 citations and a 45.3% OOS rate, meaning nearly half of those citations end with a truck parked. By comparison, 393.201B-FR's 0.7% OOS rate makes it one of the least likely codes in its category to take you off the road immediately.
That said, 396.17C-PI — No proof of periodic inspection shows up in our co-occurring data and has its own 212,081 citations at a 0.0% OOS rate — a code that often travels with 393.201B-FR because both point to the same underlying gap: maintenance documentation and physical inspection aren't keeping up with vehicle condition.
How to avoid it
The co-occurring violation pattern in our data tells a clear story about what kind of inspections produce 393.201B-FR citations. In the last 90 days, this code appeared alongside 393.9A-LCL and 393.9A-LIL (inoperable required lamps) in 95 and 85 shared inspections respectively, 396.17C-PI (no proof of periodic inspection) in 81, 393.78A-WS (defective windshield) in 76, and 396.3A1-BOS (brakes out of service) in 60. These aren't random — they describe trucks that are behind on systematic maintenance across multiple systems. Here's how to break that pattern before you reach a scale:
- Walk the frame during every pre-trip. Physically crouch and look at the cab mount points fore and aft. Look for cracked welds, missing bolts, or rubber isolators that have collapsed or pulled away from their seats.
- Check for cab movement. With the truck on flat ground, push laterally on the cab corners. Any perceptible shift or clunk indicates a mount has failed or loosened.
- Document your periodic inspection. Our data shows 396.17C-PI co-occurs with this violation in 81 inspections over 90 days. Carrying current proof of periodic inspection won't fix a broken mount, but it demonstrates a maintenance culture that reduces total violation exposure.
- Pay extra attention on Freightliner and Hino platforms. Our records show Freightliner variants account for 1,061 + 762 citations (logged under FREIGHTLIN and FRHT respectively), and Hino accounts for 717 — the top three makes by all-time citation count for this code. If you're driving one of these platforms, add mount inspection to your standing pre-trip checklist.
- Flag brake and steering findings at the same time. With 393.47E (slack adjuster defective) and 393.53B-B (steering system components worn) each co-occurring in 60+ inspections, inspectors finding a mount issue are also checking underneath. A pre-trip that catches the mount condition should also verify slack adjusters and steering linkage before departure.
- Report and repair, don't defer. Because this code is not OOS-eligible in the vast majority of encounters, it's tempting to keep rolling and schedule the repair later. Our data shows 6,710 of 6,757 citations resulted in exactly that — no immediate OOS. But each citation is a scored event in the SMS system, and deferred repairs compound into the kind of multi-violation inspection that costs fleets CSA points across several categories at once.