Commercial Driver’s License (CDL) · Skills Test Components
Pre-Trip Vehicle Inspection
On this page 6 sections
In 30 seconds
You walk the vehicle in a fixed order, seven steps from the engine compartment to the air-brake check, narrating every item out loud while pointing at it or touching it. The examiner holds a score sheet and marks off the items you name. You cannot earn credit for a check the examiner did not hear.
Why this matters
The pre-trip inspection is the first part of the skills test, and because the examiner scores it by listening to what you say and watching what you touch, an item you check silently counts as an item you never checked.
The college version
In normal terms
- Point at it, touch it, say it. If the examiner did not hear it, you did not check it.
- Use the same order every time, so the order carries you when nerves hit.
- For every part, say what it is and what you are looking for: "mounted securely, not cracked, not leaking."
- The air-brake check has numbers in it, and those numbers are graded.
Concepts in this outline
- Pre-Trip Vehicle Inspection (7-Step Script) — A fixed spoken order, done the same way every time.
- 1. Engine compartment: oil, coolant, belts, battery, air compressor — Checked cold; name each item, its condition, secure and not leaking.
- 2. Cab check/engine start: gauges, warning lights, air-pressure build-up, mirrors, seat belt — Buckle up, start, read gauges aloud, confirm air builds.
- 3. Lights check: headlights, signals, brake lights, reflectors — Every light works, lenses unbroken, reflectors the correct color.
- 4. Walk-around inspection: tires, wheels, lug nuts, frame, fuel tank, body — The clockwise walk, touching each tire, wheel, lug nut, frame rail, tank, and panel.
- 5. Signal check: turn signals, brake lights — Verified at each corner.
- 6. Final items: mirrors, windshield, wipers, horn, defroster, safety equipment — In-cab items plus extinguisher, three triangles, and spare fuses.
- 7. Air-brake check: leak-down test, low-pressure warning, spring-brake pop-out — Timed leak test, warning before 60 psi, spring brakes between 20 and 45 psi.
Eli explains
The same idea, in plain words
Explain it like I’m 10
Think of show-and-tell at school. You hold up each thing, name it, and say why it matters. Skip one, and nobody knows you brought it. The pre-trip inspection works the same way. The truck is parked, engine off, wheels chocked. The examiner walks beside you with a sheet of every part. Each part you name and describe earns credit. Miss enough and you fail before you drive. That is why instructors call this a spoken script.
The method is point, touch, say. Touch the part, name it, and say what you are checking. Step one is the engine compartment, checked with the engine cold. Say the oil is between the add and full marks. Say the coolant is at the proper level with no leaks. Coolant keeps the engine from overheating. Say the belts are not frayed or cracked. They should have no more than three-quarters of an inch of play. Say the battery is mounted tight with clean terminals. Say the air compressor, the pump that makes air for the brakes, is mounted securely. Every sentence names a part and a condition.
Step two is the cab check and engine start. Buckle up, start the engine, and read the gauges out loud. Oil pressure rising, voltmeter charging, air building, warning lights off. Step three is the lights check: low and high beams, flashers, clearance lights, reflectors. Step four is the walk-around, the longest one. At each tire, say the tread is deep enough. Steering tires need at least 4/32 inch, the others 2/32 inch. Say the sidewalls have no cuts or bulges. Say the rim is not cracked. Say the lug nuts are all there and tight, with no rust streaks. Then the frame, fuel tank, body, and doors.
Step five is the signal check at each corner. Step six is the final items in the cab. Mirrors, windshield, wipers, horn, defroster, and the safety equipment. That means a charged fire extinguisher, three reflective triangles, and spare fuses.
Step seven is the air-brake check. Engine off, brakes released, watch the gauge for one minute. Air loss must stay under the allowed amount. Apply the brakes and time again. Then pump the pedal until the low-pressure warning comes on. That must happen before 60 psi. Psi is a way to measure how hard the air is pushing. Keep pumping until the spring brakes pop out between 20 and 45 psi. A missed item costs points. On the job, that belt can snap.
Worked example
Rosa Delgado is testing for a Class A on a tractor and 53-foot trailer. She starts at the front bumper and works clockwise, hand on each part. At the steer tire she presses her thumb into the tread and says, "I am checking that the tread depth is at least 4/32 of an inch, the sidewall has no cuts or bulges, and the valve stem is capped and not leaking." At the wheel she touches each lug nut and says, "All ten present, none loose, no rust trails, no shiny threads." She names the brake chamber, slack adjuster, drum, and hose at every axle.
For the air-brake check she shuts off the engine, releases the brakes, times a minute, and says, "Pressure dropped 1 psi, under the 3 psi limit for a combination." She applies the brakes, times again, then pumps the pedal until the buzzer sounds before the gauge drops below 60 psi and the parking-brake knob pops out at 35 psi. The examiner has been checking boxes the whole time.
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