Top DOT Inspection Fails and How to Avoid Them

Every commercial driver knows the feeling: you’re cruising down I-40 or stuck in Memphis traffic when a set of flashing lights pulls you into a DOT inspection. But there’s no need to panic, because you’ve read our top DOT inspection fails and how you can dodge them like a seasoned pro.

1. Faulty Brake Systems: The #1 Offender

If there's one thing inspectors don't mess around with, it's brake violations, and for good reason. A faulty brake system is dangerous for everyone on the road. Brakes are the most common reason for failure, with inspectors pulling 2,296 commercial vehicles off the road in August 2025 alone due to brake issues.

Common Fail Points:

• Cracked or missing brake linings
• Excessive air leaks
• Out-of-adjustment brakes (especially slack adjusters)
• Damaged or worn brake drums

How to Avoid It: Daily pre-trip inspections are your best friend. Listen for air leaks, manually check your slack adjusters, and look over your brake drums for wear. Don’t skip scheduled maintenance, especially for components like the air compressor, pushrod, and S-cam.

2. Lighting Violations: Small Bulbs, Big Problems

It seems like a minor thing, but non-functioning lights can quickly escalate during an inspection. DOT officers won’t hesitate to slap you with a violation for a single burned-out clearance or taillight.

Common Fail Points:

• Broken or missing reflectors
• Inoperable turn signals
• Dim or non-functional headlights
• Inconsistent brake lights

How to Avoid It: Before every trip, do a full walk-around light check. Carry extra bulbs and fuses with you. Don’t forget to inspect trailer connectors and wiring harnesses. Corrosion and loose plugs are repeat offenders in humid conditions like our hometown of Memphis, TN.

3. Worn Tires and Bad Tread: Grip It or Skip It

Tire violations can get you parked real quick. Inspectors pay close attention to tire conditions, especially during roadside inspections.

Common Fail Points:

• Tread depth below 4/32” on steer tires or 2/32” on others
• Exposed cords or sidewall damage
• Mismatched tire sizes on the same axle
• Improper inflation or flat tires

How to Avoid It: Use a tire gauge; don’t eyeball it. Check for irregular wear patterns, which might point to bigger issues like suspension trouble or poor alignment. Rotate tires as needed and keep inflation pressures within spec.

4. Leaking Fluids: A Drip Can Sink You

Leaking engine oil, coolant, or transmission fluid not only damages your components but also will earn you a violation. Inspectors won’t overlook wet spots on your axles or puddles under your truck.

Common Fail Points:

• Oil leaks at the oil pan or valve cover
• Transmission fluid leaks at seals
• Coolant leaks near the radiator or hoses
• Fuel leaks at injectors or tanks

How to Avoid It: Get under the hood. Look for fluid trails, wet spots, or residue. During maintenance, replace gaskets and O-rings as soon as wear shows up. Don’t forget to check DEF lines and tanks, too; leaks there can trigger aftertreatment failures.

5. Suspension System Issues: Not Just a Bumpy Ride

In Memphis, with its mix of pothole-laden roads and long-haul routes, your suspension system takes a beating. If it fails inspection, you’re not going anywhere.

Common Fail Points:

• Cracked or broken leaf springs
• Deflated or leaking air suspension bags
• Missing or worn shock absorbers
• Loose or broken U-bolts

How to Avoid It: During routine inspections, check your leaf spring hangers and bushings. If you’re running air suspension, listen for leaks and monitor your ride height. Look for any uneven tilting; it might mean a bag is on its way out.

6. Loose or Missing Wheel Fasteners

Those lug nuts? They matter. A single missing or loose wheel fastener is enough to warrant an out-of-service order.

Common Fail Points:

• Rust trails indicating loose nuts
• Damaged or stripped threads
• Improper torque during the last service

How to Avoid It: Use a torque wrench during tire installs. Re-check lug nut torque after 50-100 miles post-install. Watch for signs like wheel wobble or strange vibrations.

7. Emergency Equipment Missing or Expired

DOT inspectors always check for required emergency equipment, and skipping this part of your pre-trip is a rookie mistake.

What You Need:

• Three reflective triangles
• Fully charged fire extinguisher (secured and accessible)
• Spare fuses (for applicable systems)

How to Avoid It: Do a monthly check. Ensure your fire extinguisher has its safety pin and current inspection tag. Keep triangles in the cab, not buried under your bunk.

8. Faulty Logbook or ELD Violations

Yes, your ELD or paper logs can fail you fast. This one’s especially critical for fleet drivers and OTR haulers.

Common Fail Points:

• Incomplete or falsified logs
• Uncertified daily logs
• Malfunctioning ELDs
• Failure to show the previous 7 days of logs

How to Avoid It: Double-check your entries. Make sure your ELD is synced and functioning properly. Keep backup paper logs in case of system issues. DOT officers in Tennessee don’t take kindly to “oops, I forgot.”

Avoiding DOT Failures Starts with You

There’s no getting away from it; DOT inspections are a fact of life when you’re driving commercial vehicles. But the truth is that most of the top violations are avoidable with some good old-fashioned attention to detail.

At TCB Truck Service, we see it all the time: rushed inspections, skipped maintenance, and overlooked basics leading to downtime that could’ve been avoided. Whether you’re prepping for your annual DOT, getting ready for a long haul, or just trying to keep your CSA score clean, it all starts with daily diligence and knowing what to look for.

Final Thoughts

DOT inspection failures can cost you time, money, and even your license. But with a bit of proactive maintenance and a sharp eye, you can steer clear of the common traps. Inspect your brakes, lights, tires, and fluids like your livelihood depends on it—because it does. 

Whether you're rolling through downtown Memphis or hauling across state lines, keeping your truck inspection-ready keeps you on the move. Schedule your next inspection prep or preventive maintenance with our team at TCB Truck Service. Keep your rig rolling and your CSA score clean.