TruckCodex

393.43D — Brake - relay emergency valve

FMCSA violation code under Vehicle Maintenance. 4,729 events recorded in roadside inspections. Severity weight: 7.

Severity Weight
7
OOS Eligible
No
BASIC Category
Vehicle Maintenance
Total Events
4,729
Code
393.43D
Code System
FMCSR
BASIC Category
Vehicle Maintenance
OOS Eligible
No
Severity Weight
7
Violation Group
—
Total Events
4,729
Carriers Cited
3,739

Violation Description

Relay or emergency valve on CMV is defective or malfunctioning.

About This Violation Code

Code 393.43D falls under the Vehicle Maintenance BASIC category in FMCSA's Safety Measurement System (SMS). It carries a severity weight of 7 (scale 1-10, higher = more severe).

When this violation is cited during a roadside inspection, it contributes to the carrier's Vehicle Maintenance BASIC score. Carriers with high BASIC percentiles may be prioritized for FMCSA interventions including warning letters, investigations, or compliance reviews.

Regulatory Reference

Federal Motor Carrier Safety Regulations

This violation references 49 CFR 393.43D in the Federal Motor Carrier Safety Regulations.

View on eCFR.gov →FMCSA Violations Search →
Events (all time)
4,729
OOS Events
4,415
OOS Rate
93.4%
Top State (180d)
Texas
885 events

Top Enforcing States

Where 393.43D is most commonly cited (last 180 days)

1.Texas
885
OOS 91.2%
2.Iowa
273
OOS 98.2%
3.North Carolina
65
OOS 100.0%
4.Illinois
45
OOS 100.0%
5.New Mexico
16
OOS 100.0%
6.Kentucky
1
OOS 100.0%

Click a state to see roadside inspection activity, top stations, and carrier profiles in that jurisdiction.

Citation Trend (12 months)

Monthly count of 393.43D citations. Red bars mark months with OOS-triggering citations.

107
Apr
298
May
278
Jun
288
Jul
313
Aug
268
Sep
328
Oct
256
Nov
218
Dec
190
Jan
233
Feb
247
Mar
6
Apr

Most Active Stations

Inspection stations citing 393.43D most often (last 180 days)

1.39 - I35 SB MM 212 NORTHWOOD
65
OOS 100.0%
2.IH10 WB WINNIE SCALE
59
OOS 86.4%
3.IH-0820 IN TARRANT CO. (0-34)
29
OOS 100.0%
4.TX302 MENTONE SCALE
24
OOS 100.0%
5.200 E SAM HOUSTON PK
18
OOS 100.0%
6.10 - I35 NB MM 30 OSCEOLA
14
OOS 100.0%
7.IH 10 MP 404
14
OOS 100.0%
8.US-0075 IN COLLIN CO. (226-256
14
OOS 100.0%
9.US-0287 IN ELLIS CO. (484-520)
13
OOS 100.0%
10.16 - I380 SB MM 53 BRANDON
10
OOS 100.0%

Often Cited Together

Other violations commonly found on the same inspection (last 90 days)

396.17C455 co-occurrences392.2RG432 co-occurrences393.48A427 co-occurrences393.9319 co-occurrences393.95A205 co-occurrences390.21(a)178 co-occurrences393.95F166 co-occurrences383.23A2155 co-occurrences396.3A1BOS125 co-occurrences391.41APC117 co-occurrences

Citation patterns suggest related root causes (e.g., HOS violations paired with logbook errors).

Top Carriers Cited

Ranked by frequency • 3,739 carriers total • Page 1 of 150

Top Carriers with 393.43D Violations

Showing 25 of 3,739

fmcsa-violations
Top Carriers with 393.43D Violations
#CarrierUSDOT# Violations
#1SUPLICIUM TRANSPORT LLC438125512
#2AUTO HAUL EXPRESS LLC432932511
#3ACME TRUCK LINE INC527679
#4HABANA TRANSPORTATION LLC44277958
#5M&M SALAZAR CONSTRUCTION LLC19623558
#6TRANSPORT KING LLC36082498
#7BENNETT MOTOR EXPRESS LLC926938
#8SAKARA LLC44295308
#9POLO TRANSPORTATION LLC42481148
#10FALCON UTILITY LLC38413688
#11USA DEBUSK LLC22979538
#12ASV XPRESS LLC43893017
#13ZAYCO TRUXE LLC42552737
#14EAR TELECOMMUNICATIONS LLC43322837
#15SDC UNDERGROUND UTILITY LLC33115827
#16HORIZEN LLC44002347
#17STX UNDERGROUND LLC36061196
#18LA BORING LLC36248856
#19JAM TRANSPORT LLC45161436
#20A&B SERVICE AND RENTAL LLC42797206
#21DIGCO UTILITY CONSTRUCTION LP11302056
#22PROFESSIONAL TRAFFIC CONTROL LLC24913246
#23K1K TRANS LLC42823916
#24HAULDEX LLC44893506
#25ALLIED FOUNDATION SPECIALIST INC29978546

Recent Inspections

Latest inspections where 393.43D was cited • 4,729 total events • Page 1 of 190

Recent Inspections with 393.43D

Showing 25 of 4,729

fmcsa-inspections
Recent Inspections with 393.43D
DateReport #StateLevelOOS
Apr 2, 202687486791ILLevel 1Yes
Apr 1, 202687487141TXLevel 2Yes
Apr 1, 202687487298TXLevel 2Yes
Apr 1, 202687488231TXLevel 2Yes
Apr 1, 202687477642ILLevel 1Yes
Mar 31, 202687459887NCLevel 1Yes
Mar 31, 202687465980ILLevel 1Yes
Mar 31, 202687465684IALevel 1Yes
Mar 31, 202687467640TXLevel 1Yes
Mar 31, 202687465848ILLevel 1Yes
Mar 31, 202687478783TXLevel 1Yes
Mar 30, 202687453566ILLevel 1Yes
Mar 30, 202687467089TXLevel 2Yes
Mar 30, 202687453037IALevel 2Yes
Mar 30, 202687468010TXLevel 2Yes
Mar 30, 202687453631ILLevel 1Yes
Mar 30, 202687479483TXLevel 2Yes
Mar 29, 202687466572TXLevel 2Yes
Mar 29, 202687453293IALevel 1Yes
Mar 29, 202687466786TXLevel 2Yes
Mar 28, 202687466494TXLevel 2Yes
Mar 28, 202687453404IALevel 1Yes
Mar 28, 202687467239TXLevel 2Yes
Mar 27, 202687468672TXLevel 2Yes
Mar 27, 202687479492TXLevel 2Yes

Data sources & freshness

FMCSA Vehicle Inspections and Violations
Unknown freshness
Federal Motor Carrier Safety Regulations (49 CFR)
Unknown freshness

Related records

CategoryAll Vehicle Maintenance Violations
Browse all violation codes in the Vehicle Maintenance BASIC
IndexAll Violation Codes
FMCSR violation codes by BASIC category
ReferenceFMCSA Roadside Inspections
Inspection levels and procedures
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