What happens when you're cited for 393.47C brake actuators defects? Out-of-service risk, CSA points, next steps, and state-by-state enforcement data.
Ranks #779 of 3,146 FMCSR codes by citation frequency • OOS rate of 7.4% is below the FMCSR-wide average of 33.3%.
Brake actuators, chambers, or other brake components are defective or not functioning properly.
Direct answers grounded in TruckCodex inspection data
No—not automatically. Across our 13 million inspection records, 393.47C is not OOS-eligible by regulation. However, 62 trucks out of 811 cited for this violation were placed out of service anyway, giving a 7.6% OOS rate. This is substantially lower than the 31.4% average OOS rate across all FMCSR codes. Most drivers cited for defective brake actuators are allowed to continue operating, but the violation still requires repair and carries CSA points.
A single 393.47C citation carries a CSA severity weight of 7 points. The actual impact on your Unsafe Driving or Vehicle Maintenance BASIC score depends on how many citations you accumulate in a 30-month window and your carrier's overall safety profile. One citation is manageable; repeated citations compound quickly. Fleet safety managers should track these alongside co-occurring brake codes to identify systemic maintenance gaps.
First: do not ignore it. Your next steps:
It's moderate-severity in the brake category. Our data shows 393.47C has a 7.6% OOS rate—much lower than the 45.3% OOS rate for general brake inspection/repair violations (396.3(a)(1)) but similar to other defective-component codes. Slack adjuster defects (393.47E), which co-occur in 53 of our recent 393.47C inspections, carry a 0.0% OOS rate. The gap matters: actuator/chamber defects are treated as less critical than some other brake failures, but they still affect stopping power and must be fixed.
Yes, if you have grounds. DataQs (Docket Quality System) allows drivers and carriers to challenge citations within 30 days of the inspection. For 393.47C, valid challenges typically involve:
Equipment-condition findings (like brake actuator defects) are harder to dispute than paperwork violations—the inspector's notes and photos matter. File with evidence: maintenance records, repair invoices, or photos of the corrected system.
Over the last 180 days, our inspection records show:
Texas dominates the volume but has a lower OOS rate—most Texas drivers escape out-of-service. Illinois, though citing far fewer trucks, places a third of them out of service, suggesting stricter enforcement. If you operate in Texas frequently, brake maintenance is a high-priority compliance item.
Very urgent—repair within 48 hours. Our 90-day trend shows 131 citations for defective brake actuators, with spikes in July (9 OOS events) and January (5 OOS events). Even though the code is not OOS-eligible by rule, individual inspectors place trucks out of service in ~7–8% of cases, and a brake system flagged as defective can trigger secondary violations—notably 396.3A1BOS (brake out-of-service threshold), which appeared in 33 co-occurring inspections. Delayed repair compounds your CSA risk and increases the chance of a more serious follow-up citation.
Across all citations in our database, Freightliner (FRHT) leads by far with 269 citations, followed by Kenworth (KW) with 149. This reflects the market dominance of these heavy-duty makes, not necessarily inferior brake quality—citation volume tracks fleet size and miles. Peterbilt (52), Volvo (52), and International (48) round out the top five. If you drive a Freightliner or Kenworth, proactive brake maintenance and inspection (every pre-trip and every 10,000 miles) should be standard practice.
Where 393.47C is most commonly cited (last 180 days)
Other violations commonly found on the same inspection (last 90 days)
TruckCodex aggregates official public-sector datasets. See the Source registry for dataset-level coverage and the Freshness log for last-import timestamps.
Census, SAFER, SMS, Licensing & Insurance (L&I), roadside inspections, crashes, and authority history.
Vehicle recall campaigns, defect investigations, and consumer safety complaints (SCRS).
Cross-border carrier registry and Canadian recall campaigns where applicable.
TruckCodex is an independent aggregator; it is not affiliated with FMCSA, NHTSA, EIA, or Transport Canada. Always verify compliance-critical information directly with the originating agency.