393.43(e) Brake Relay Valve Citation: What Drivers Need to Know

No. Across our 13 million+ inspection records, 393.43(e) citations have never resulted in an out-of-service placement—the OOS rate is 0.0%. This contrasts sharply with the all-FMCSR average OOS rate of 31.4%, making this one of the most lenient violations you can receive. You can continue operating while you arrange repair, though the defect should be corrected promptly.

A single 393.43(e) citation carries a CSA severity weight of 7 points. The actual impact on your Safety BASIC score depends on how many citations you accumulate in a 30-day rolling window. One citation alone may not trigger intervention, but it does add to your vehicle maintenance BASIC. Review your CSA portal at SafetySnapshot.fmcsa.dot.gov to see your current total.

Take these steps now:

1. Document the defect — photograph the relay or emergency valve and the inspector's notes.
2. Schedule repair — contact a certified brake shop; relay valves are critical brake components.
3. Get proof of repair — retain receipts and work orders showing the valve was replaced or repaired.
4. Report to your carrier — if you're a driver, notify dispatch and safety immediately.
5. Keep inspection records — file all repair documentation with your vehicle maintenance logs.

Do not defer this repair; brake system components are subject to follow-up inspections.

Our data shows 393.43(e) is among the least-cited brake and maintenance violations. It ranks #1050 of 3,036 FMCSR codes by volume (only 337 all-time citations). Compare this to similar defects: slack adjuster failures (393.47E) have 180,363 citations, and general maintenance violations (396.3(a)(1)) hit 236,919. The fact that 393.43(e) is rarely cited and never placed out of service suggests relay valve defects are either less common or caught less often at roadside inspections.

Yes, you can submit a DataQS (DataQ) challenge through FMCSA's Roadside Data Repository (RDR) system. Since 393.43(e) involves inspection of a physical component, contestability depends on whether the inspector's conclusion was correct. If you believe the relay valve was functional or the defect was misidentified, gather photographic or technical evidence and file within the DataQS window. Consult your carrier's safety manager or a compliance professional for guidance on your specific case.

Enforcement is extremely rare. Our inspection records show zero citations for 393.43(e) in the last 12 months and zero in the last 90 days. All 337 all-time citations in our database are distributed across years, suggesting this violation is either uncommon in the field or not a focus of routine roadside inspections. This low volume means you're unlikely to encounter repeat citations unless your vehicle has a chronic relay valve issue.

Across our inspection records, Freightliner tractors lead with 124 citations, followed by Utility trailers (77 citations) and Wabash National trailers (66 citations). Kenworth (62) and International (61) also appear frequently. The prevalence of Freightliner and utility equipment suggests these platforms may have higher failure rates for relay valves, possibly due to age or maintenance patterns in the fleets that operate them.

Vehicle maintenance citations like 393.43(e) are attributed to the carrier's Unsafe Driving and Vehicle Maintenance BASICs under FMCSA's CSA methodology. The violation stays with the carrier entity, not the driver. However, if the driver operates multiple vehicles for the same carrier, patterns of maintenance neglect may reflect on driver safety behavior. As a driver, you benefit when your carrier maintains equipment properly—it reduces your citation exposure.