Buying a used semi truck: inspection checklist

Before you look at a truck

Get the VIN before you drive anywhere. Most of the paperwork checks on this page take the VIN and a few minutes. If a seller won't give it to you, move on.

• Know where the truck will run. If you plan to haul in or through California, the truck has to meet CARB rules (see below). That alone rules out many older trucks.
• Know what you'll pull. Axle setup, engine and gearing should fit the freight and the lanes you plan to run.
• Plan a mechanic's inspection. A walk-around by you is a first screen, not a substitute for a qualified mechanic with the truck on a lift and a scan tool on the engine.
• Set your budget per mile, not per truck. Run the payment through the cost per mile calculator before you fall in love with a truck.

Financing it? Our guide on how to finance a truck covers loans and quotes. Not sure whether to buy at all? Read leasing vs. buying a truck.

Check the paperwork first

Paper problems are cheaper to find than mechanical ones. Do these before you pay for an inspection.

• Decode the VIN with NHTSA's free decoder, or our VIN decoder tool. Year, make, model and engine should match the truck, the title and the ad.
• Pull an NMVTIS report. The Department of Justice's National Motor Vehicle Title Information System shows title data, the latest reported odometer reading and brand history such as junk, salvage or flood. Buy it from an approved provider listed on vehiclehistory.bja.ojp.gov. DOJ warns that it doesn't hold everything in a state's title record, so get the state record too.
• Check the title. The seller's name must match. If a lender is listed, get the lien release (or a payoff arranged through the lender) before money changes hands.
• Ask for the last annual inspection report. Under 49 CFR 396.17, a carrier can't use a commercial motor vehicle unless it passed a periodic inspection in the preceding 12 months and proof is on the vehicle. The report (49 CFR 396.21) shows who inspected it, when, and what was checked.
• Ask for maintenance records. A motor carrier must keep inspection, repair and maintenance records for each vehicle for 1 year, and for 6 months after the vehicle leaves its control (49 CFR 396.3). If the seller is a carrier, those records should exist. Ask for copies now.
• Note the model year for ELD rules. Trucks manufactured before model year 2000, as shown by the VIN on the registration, are exempt from the ELD requirement under 49 CFR 395.8. Paper logs still apply.

Frame, suspension and coupling

Appendix A to Part 396 lists the defects that fail an annual inspection. Use it as your minimum. A truck that would fail today needs repairs before it can legally work.

• Frame rails: any cracked, broken, loose or sagging frame member fails. So do loose or missing fasteners on parts attached to the frame, including the engine, transmission, steering gear, suspension and fifth wheel. Look closely for welds and fresh paint over repairs.
• Tire and wheel clearance: the body or frame must not touch any tire or wheel.
• Suspension: look for cracked, broken or missing springs and torque, radius or tracking parts, and for air suspension leaks.
• Fifth wheel and mounting: check for cracks, loose mounting and a latch that locks properly.
• Exhaust: an exhaust leak forward of or directly below the cab or sleeper fails inspection.
• Rust and body: heavy corrosion on the frame, crossmembers, cab mounts and air tanks costs money even when it doesn't fail inspection yet.

Engine, ECM and aftertreatment (DPF, SCR, DEF)

On a modern diesel, the emissions system can cost as much to fix as the engine. Have a mechanic check:

• ECM data and fault codes. A scan shows active and stored codes, engine hours, idle time and how the truck has been run. Compare engine hours and miles with the odometer and the NMVTIS reading.
• DPF (diesel particulate filter). Ask when it was last cleaned or replaced, and look at regeneration history if the scan tool shows it.
• SCR and DEF. Check for DEF quality or dosing codes, crystals around the injector and lines, and sensor faults.
• Signs of tampering. Missing parts, a straight pipe, or a "delete" tune. Under the Clean Air Act (42 U.S.C. 7522), it's illegal to remove or knowingly disable emissions equipment, or to sell or install parts made to defeat it. A deleted truck can also fail California's Clean Truck Check.
• DEF derate software. In August 2025, EPA issued guidance urging engine makers to update DEF software on trucks already in use so they don't suffer sudden power loss. Ask the dealer or the engine maker whether an update exists for this engine and whether it was installed.
• The basics: oil analysis if the seller allows it, blow-by, leaks, coolant in the oil, turbo play, clutch and transmission behavior on a test drive.

Tires, wheels and brakes

Tires and brakes are where a used truck most often fails a roadside inspection. The tread rules are in 49 CFR 393.75:

• Don't measure on tie bars, humps or fillets.
• No tire may have ply or belt material showing, tread or sidewall separation, a flat or audible leak, or a cut down to the ply or belt.
• A regrooved tire with a load capacity of 4,920 lbs or more can't go on the front wheels of a truck or tractor.
• Wheels and rims: look for cracks, loose or missing lug nuts and rust streaks from the studs.
• Brakes: Appendix A fails missing or broken shoes, linings, pads, springs and other parts, audible air leaks at a brake chamber, and pushrod stroke past the readjustment limit. Ask the mechanic to check stroke on every chamber.
• ABS: truck tractors built on or after March 1, 1997 must have antilock brakes with a working malfunction lamp (49 CFR 393.55). A lamp that stays on is a repair to price in.

Budget for tires and brake work in your offer. Our truck maintenance schedule shows what comes due next.

Used semi checklist

Print this or keep it on your phone. Don't pay until every line is checked or priced into the deal.

For daily checks once the truck is yours, use our pre-trip inspection checklist.

California: Truck and Bus rule and Clean Truck Check

If the truck will ever work in California, check CARB's rules before you buy. CARB's own pages, as of this writing:

• Truck and Bus Regulation. Since January 1, 2023, diesel vehicles over 14,000 lbs GVWR operating in California must have a 2010 or newer engine and emission system, with few exceptions. The DMV denies registration to trucks that don't comply. You can check a truck's status on CARB's TruckStop site.
• Clean Truck Check applies to nearly all diesel and alternative-fuel heavy-duty vehicles over 14,000 lbs GVWR that operate on California roads, even if they're registered outside California. To be compliant, the owner reports the vehicle in CARB's CTC-VIS system, pays the annual compliance fee, submits passing emissions tests from a CARB-credentialed tester, and clears any open violations.
• Testing frequency. Most vehicles must show compliance every six months. CARB says that starting October 2027, vehicles with on-board diagnostics (OBD) will be tested four times a year.
• When you buy. CARB says owners must update their CTC-VIS vehicle information within 30 calendar days of buying or selling a vehicle. You can report a truck with a temporary plate.
• CARB offers a limited Five-Day Pass for some vehicles. Check eligibility on CARB's site before you count on it.

CARB rules change often. Confirm the current requirements on ww2.arb.ca.gov or call CARB's diesel hotline at (866) 634-3735 before you buy a truck for California work. More on the state on our California dispatch page.

Form 2290 and registration when you buy

A truck with a taxable gross weight of 55,000 lbs or more owes the federal heavy vehicle use tax (HVUT) on Form 2290. States use the IRS-stamped Schedule 1 as proof of payment when you register. When you buy used:

• Keep proof of what happened before you. The IRS says the buyer must keep records showing whether the tax was paid or suspended for the period before the truck was registered in the buyer's name. A signed, dated statement from the seller or dealer works.
• If the seller already paid for this period and you buy from a private seller, the IRS lets you skip the tax for the month of sale when your first use is in that month. You pay a prorated tax starting the next month. A copy of the seller's stamped Schedule 1 is one way to confirm the seller paid. See the Form 2290 instructions for the details and due date.
• If the seller suspended the tax (expected use of 5,000 miles or less, 7,500 for agricultural vehicles), the seller must give you a statement with the seller's name, address and EIN, the VIN, the sale date, odometer readings at the start of the period and at the sale, and your name, address and EIN. You attach it to your Form 2290. The mileage limit counts total miles in the period, no matter how many owners. Once it's exceeded, the tax is due.
• Registration and IRP. Plan your own registration before the first load. Under the International Registration Plan, you need apportioned plates if you run in two or more jurisdictions with a power unit that has two axles and more than 26,000 lbs, three or more axles at any weight, or a combination over 26,000 lbs. You apply in your base jurisdiction. See our IFTA and IRP checklist.

Step-by-step filing help is in our Form 2290 guide.

Questions carriers ask