Violation code

390.21TC

Improper size/location/color of required CMV marking(s).

Not in SMSOOS· FMCSA A&I All Violations

390.21TC is a Other violation under 49 CFR §390.21TC. It is an out-of-service violation; it is not scored in the SMS. Nationally it was cited 11,908 times in the last five years, with an OOS rate of 0.0%.

📊

National roadside inspection stats

as of 6/20/2026

Inspections

11,800

that found this code

Violations

11,908

total written

OOS rate

0.0%

2 OOS

Source: FMCSA roadside inspection data (last 5 years). The OOS rate is the share of these violations that led the officer to mark the driver or vehicle out of service.

📎

Not used in SMS BASIC scoring

Recorded on your inspection report and visible on the PSP, but contributes 0 points to CSA BASIC scores — even if cited Out-of-Service.

Violation group: Other
Regulation §: 390.21TC
Severity weight: N/A
Used in SMS: No
Status: Active
Updated: 6/20/2026

Last updated June 2026

⚡

Think this violation was written incorrectly?

Generate a polished DataQs challenge letter for 390.21TC in about 5 seconds. AI quotes the CFR, predicts your grant chance.

⚡ Draft a challenge →

📚

Challenging 390.21TC through FMCSA DataQs

If this violation was written incorrectly, here are the angles trucking-safety managers use to contest it. Playbook: Codes not used in SMS scoring.

Common ways to challenge this code

Not used in SMS — should not affect BASIC
This code is on the inspection report but is excluded from SMS BASIC scoring per Appendix A. Use DataQs to correct the underlying data quality issue if the code was written in error, but understand it does not affect the CSA percentile.
Evidence that wins
- ✓FMCSA SMS Methodology Appendix A reference
- ✓Underlying inspection report

Common pitfalls — avoid these

⚠These codes still appear on PSP — challenge the data if the cite was wrong

⚡ Draft a challenge for 390.21TC →Read the DataQs guide first

Other Other codes

Codes under the same FMCSA violation group

❓

Frequently asked questions about 390.21TC

What does violation 390.21TC mean?

390.21TC is the FMCSA roadside-inspection violation code for "Improper size/location/color of required CMV marking(s).", part of the Other group, cited under 49 CFR §390.21TC.

What BASIC does 390.21TC affect?

390.21TC is not scored in any CSA BASIC. It is recorded on the inspection report and appears on the PSP, but it contributes 0 points to a carrier's SMS BASIC percentiles.

Is 390.21TC an out-of-service (OOS) violation?

Yes. 390.21TC is an out-of-service violation, meaning the driver or vehicle can be placed out of service at the roadside until the issue is corrected. OOS violations also add an extra severity point in SMS scoring.

How many CSA points does 390.21TC add?

390.21TC adds 0 CSA points because it is not used in SMS scoring, even when written out of service.

Can 390.21TC be challenged through DataQs?

Yes. If you believe 390.21TC was recorded in error, you can file a Request for Data Review (RDR) through the FMCSA DataQs system with supporting evidence. A successful challenge can remove or correct the violation on your record.

Keep going

CSA points calculator How to challenge a violation Draft a DataQs letter for 390.21TC Carrier CSA lookup CSA glossary