FMCSR 393.23: Required Lamp Not Powered by Vehicle Electric — FAQs

It depends on the inspector, but the historical odds are high. Even though 393.23 is not officially designated as an OOS-eligible code, our inspection records show it has resulted in an out-of-service placement in 4,951 of 5,781 all-time citations — an 85.6% OOS rate. That is nearly three times the all-FMCSR average of 31.4%. Inspectors appear to treat a required lamp that isn't drawing power from the vehicle's electrical system as a serious enough defect to pull the truck regardless of the formal OOS eligibility status. Do not assume you'll roll away just because the code isn't flagged OOS-eligible.

The STATISTICS block for 393.23 does not include a published severity weight, so a specific point value cannot be confirmed here. What the data does confirm is that this violation falls in the Vehicle Maintenance BASIC, which means it affects both the carrier's Safety Measurement System score and the driver's Inspection Selection System profile. Violations cited within the last 30 days carry a 3× time-weight multiplier under CSA, so a recent citation hits hardest. Because the 85.6% OOS rate signals that inspectors treat this violation seriously, the downstream CSA impact is compounded if you are placed out of service alongside it.

Get the lamp back on vehicle electrical power before your next dispatch. Beyond that, look closely at your inspection report — across the last 90 days our records show 393.23 almost never appears alone. The most common companions are 393.9 (inoperable required lamp, 5 shared inspections), 393.11TL and 393.11 (lighting devices/reflectors, 3 each), and 393.78 (windshield condition, 3 shared inspections). That pattern means a full lighting and glazing walkround is worth doing immediately. Also check your exhaust routing: 393.83G appeared in 4 shared inspections in the same 90-day window. Fix co-violations before your next stop — inspectors who caught one often catch the rest.

Yes — its OOS rate is dramatically higher than comparable codes. Across our database the all-FMCSR average OOS rate is 31.4%. The closest peer code, 393.9(a) (inoperable required lamps), has a 15.4% OOS rate across 660,737 citations. The broader 393.9 code sits at 6.9% across 180,097 citations, and 393.11 (lighting devices/reflectors) is just 1.8% across 179,734 citations. By contrast, 393.23 comes in at 85.6% — meaning inspectors place trucks out of service on this code at a rate roughly 55 times higher than 393.11. The violation involves a lamp that has been cut off from the vehicle's electrical system entirely, which explains the harsher response.

Yes, you can submit a Request for Data Review (RDR) through FMCSA's DataQs system for any roadside inspection finding. Because 393.23 is an equipment violation rather than a documentation deficiency, a successful challenge typically requires showing either that the inspector's finding was in error — for example, the lamp was in fact connected to vehicle electrical power — or that the citation was entered incorrectly. Gather photos taken at or near the inspection time, repair orders, and any driver or carrier notes from the day. Submit through the DataQs portal referencing the specific inspection report number. State agencies review equipment-based RDRs, so response times vary. The 85.6% OOS rate in our records suggests inspectors document this finding carefully, so a clear paper trail matters.

Texas leads by a wide margin in the last 180 days. Our inspection records show Texas issued 26 citations with a 50.0% OOS rate, making it the top enforcement state for this code in that window. North Carolina follows with 4 citations (50.0% OOS rate), and Iowa comes in third with 2 citations (50.0% OOS rate). New Mexico recorded 1 citation with a 0.0% OOS rate in the same period. If your lanes run through Texas, this code warrants extra pre-trip attention — more than half of all recent citations originated there.

Do not wait. The 85.6% all-time OOS rate means there is a very high probability the next inspector who finds this defect will park your truck on the spot. Recent monthly trend data reinforces urgency: citations jumped to 11 in December 2025 (7 OOS) and 10 in July 2025 (5 OOS), showing active enforcement in both summer and winter months. The last 90 days alone logged 12 citations. Unlike a paperwork issue that can be corrected administratively, a lamp not drawing power from the vehicle's electrical system is a physical defect that must be repaired before the truck re-enters service. A shop visit now is far less costly than a roadside OOS order mid-route.

Both are affected, but in different ways. Under FMCSA's CSA system, equipment violations like 393.23 are recorded against the carrier's USDOT number in the Vehicle Maintenance BASIC, which influences the carrier's Safety Measurement System percentile. The driver's record is tied to the inspection through their CDL, affecting their Inspection Selection System score and roadside scrutiny going forward. Our all-time data shows major carriers are not immune: J B HUNT TRANSPORT INC leads with 33 citations, followed by UNITED PARCEL SERVICE INC with 27 and XPO LOGISTICS FREIGHT INC and EVANS DELIVERY COMPANY INC each with 22. Both carrier safety scores and individual driver profiles take the hit.