FMCSR 393.28 Wiring Violations: OOS Risk, CSA Points & What to Do

Almost certainly not — but it has happened. Across 6,422 all-time citations in our inspection records, 393.28 carries a 1.6% out-of-service rate, meaning 102 vehicles were placed OOS while 6,320 were not. For context, the all-FMCSR average OOS rate is 31.4%, so 393.28 sits far below typical enforcement thresholds. That said, Illinois inspectors placed 4 of 21 cited vehicles OOS in the last 180 days alone — a 19.0% local rate — which shows that inspector discretion and wiring severity matter. Fix the defect before your next inspection regardless.

A 393.28 citation carries a CSA severity weight of 3. That base number is then multiplied depending on how recently the violation occurred: inspections within the last 6 months receive a 3× time-weight multiplier, the next 6 months a 2×, and the final tier a 1×. So a fresh 393.28 citation effectively contributes 9 weighted points to your Vehicle Maintenance BASIC score during the highest-multiplier window. Because CSA scores are carrier-based, repeated citations across a fleet compound quickly — our records show 1,480 393.28 citations in the last 12 months alone.

Act on the wiring defect before your next trip, and look beyond the wire itself. Our inspection records show that 393.28 frequently appears alongside other violations in the same inspection: 393.9 (Inoperable Required Lamp) co-occurred in 160 shared inspections in the last 90 days, 393.78 (Windshield condition defective) in 97, and 396.5B (Fuel system leak) in 85. That pattern suggests inspectors writing 393.28 are doing a thorough walk-around.

Immediate steps:

1. Have a qualified technician inspect and repair all wiring — secure, protect, and properly route every affected harness.
2. Check all required lamps (393.9), windshield condition (393.78), and fuel system (396.5B) at the same time.
3. Document the repair with a dated work order.
4. Review your most recent periodic inspection for related items.

Relatively speaking, no — but don't dismiss it. At 1.6% OOS, 393.28 is far less likely to park your truck than most peer codes in the Vehicle Maintenance category. For comparison, our database shows 396.3(a)(1) — general inspection and maintenance — carries a 45.3% OOS rate across 236,919 citations, and even 393.9(a) inoperable required lamps hits 15.4% across 660,737 citations. The 393.28 OOS rate is also dramatically below the all-FMCSR average of 31.4%. Where it does sting is CSA accumulation: at severity weight 3, repeated citations chip away at your Vehicle Maintenance BASIC steadily, even without an OOS event.

Yes, you can file a DataQs Request for Data Review (RDR) to challenge a 393.28 citation. Because this is an equipment-condition violation rather than a documentation deficiency, a successful challenge typically requires evidence that the wiring was actually compliant at the time of inspection — think timestamped repair records, photos taken before or during the inspection, or a clear factual error in the inspection report (wrong vehicle, wrong code applied). DataQs challenges are evaluated by the issuing state agency, not FMCSA directly. If the state agrees, the violation is removed from your PSP and your carrier's SMS record. Given that 393.28 is ranked #300 of 3,036 FMCSR codes by citation volume, inspectors writing it generally have a specific defect to point to — make sure your documentation is airtight before filing.

Texas dominates by a wide margin. In the last 180 days, our inspection records show Texas issued 739 citations for 393.28 — more than all other states combined in that window. Illinois is a distant second at 21 citations, but with a notably higher OOS rate of 19.0% (4 of 21 vehicles placed OOS). Iowa ranks third with 6 citations, also with a 16.7% OOS rate. If you run cross-border corridors into Texas, wiring condition should be a pre-trip priority. Illinois and Iowa show fewer stops but stricter OOS outcomes when they do cite.

Don't wait. Even though 393.28 is not formally OOS-eligible, our records show 347 citations in just the last 90 days, and citation volume has been running between 103 and 163 per month for most of the past year. Improper or inadequately protected wiring is also a fire risk — our co-occurrence data shows 396.5B (Fuel system leak) appearing in 85 shared inspections in the last 90 days, a combination that elevates real-world hazard well beyond the CSA score. At a severity weight of 3 per citation, letting the defect ride into a second inspection doubles your CSA exposure. Fix it at the next safe stop, document it, and verify the repair covers adjacent systems.

Both feel the impact, but in different ways. Equipment violations like 393.28 land on the carrier's Vehicle Maintenance BASIC in FMCSA's SMS system, since the carrier is responsible for keeping the CMV in safe operating condition. The driver's Pre-Employment Screening Program (PSP) record also captures the inspection event, which prospective employers can see. Our records show that the carriers with the highest 393.28 citation counts — such as RUBEN CARLOS TREVINO SANCHEZ (USDOT 1649689) with 65 all-time citations — accumulate enough Vehicle Maintenance BASIC exposure to attract intervention. Drivers who repeatedly appear in inspections with wiring defects may find those PSP records affecting hiring decisions even when they aren't the ones responsible for pre-trip maintenance.