A useful CDL pre-trip checklist should help you do three things for every item: identify the component, describe the unsafe condition you are checking for, and explain why it matters.
This page gives you a repeatable Class A practice route. Your state CDL manual, examiner instructions, and test vehicle control the exact sequence, wording, limits, and scoring. Compare this checklist with your state’s current manual and the vehicle-specific information supplied by your school or employer.
Know your weak section before you rehearse the whole truck. Take the Pre-Trip Inspection diagnostic and use the result to decide what to review first.
For each item, practice a short pattern: “This is the component. It is securely mounted, not damaged, and shows no component-specific defect. It matters because safety reason.” Do not memorize a measurement from the internet when the current state manual or test vehicle supplies the applicable value.
1. Engine Compartment (Under the Hood)
Start your inspection here. You must point to or touch every item and explain what you are checking (e.g., “Not cracked, bent, or broken; no leaks”).
- Fluid Leaks: Look under the vehicle for puddles of oil, coolant, or power steering fluid.
- Oil Level: Pull dipstick, wipe, re-insert, and check level is above the refill mark.
- Coolant Level: Check sight glass or remove cap (ONLY when cool).
- Power Steering Fluid: Check dipstick level.
- Belts: Check the applicable alternator, water-pump, and power-steering belts. They must be secure and not cracked or frayed; use the current manual’s play limit.
- Air Compressor: Securely mounted, not leaking air or oil. Mention if it is gear-driven.
2. In-Cab Inspection (The “Safe Start”)
Climb in using 3 points of contact and buckle up immediately.
- Safety Belt: Latches securely, not frayed.
- Emergency Equipment: Spare fuses, 3 reflective triangles, fire extinguisher (fully charged & rated).
- Safe Start: Gear in neutral, clutch in (if manual), start engine. Check ABS light comes on and goes off.
- Gauges:
- Oil Pressure: Rising to normal operating range.
- Voltmeter: 12-14 Volts.
- Air Pressure: Building normally to the cut-out range specified for the vehicle and state test.
- Windshield & Wipers: Clean glass, no cracks. Wipers work smoothly with washer fluid.
- Horns: Test both City (Electric) and Highway (Air) horns.
3. The Critical Air Brake Check (L.A.B.)
Air-brake checks are a hands-on demonstration. The following values are common federal/manual baselines, but your current state procedure controls the exact order and scoring.
- L - Leaks: Turn engine OFF, key ON. Release parking brakes. Press foot brake and hold for 1 minute. You should not lose more than 4 psi (Class A) or 3 psi (Class B).
- A - Alarm: Fan the brakes. The Low Air Warning light/buzzer must come on before pressure drops below 60 psi.
- B - Button: Continue fanning. The tractor and trailer protection valves (buttons) must pop out between 20 and 45 psi.
4. Coupling System (Tractor-Trailer Connection)
A failure here is catastrophic on the road. Inspect this area thoroughly.
- Air Lines: Red (Emergency) and Blue (Service) lines connected to glad hands. No leaks. Rubber seals soft and intact.
- Electric Line: Green line plugged in firmly, safety latch locked.
- Fifth Wheel Skid Plate: Properly greased, securely mounted to the frame (no missing bolts).
- Kingpin & Locking Jaws: CRITICAL: Look under the trailer! Ensure locking jaws are fully closed around the shank of the kingpin.
- Release Arm: In the engaged (locked) position.
- Sliding 5th Wheel: Locking pins are fully engaged.
5. Wheels & Tires (The “ICD” Rule)
Check every single tire on the truck and trailer using the ICD method.
- I - Inflation: Check against the correct specification for the vehicle and tire; do not assume every truck uses 100 PSI. Valve stems should be serviceable and protected as required.
- C - Condition: No cuts, bulges, or sidewall damage. Even wear.
- D - Depth: Tread depth must be at least 4/32” (Steer tires) and 2/32” (Drive/Trailer tires).
6. Lights & Reflectors
Finally, do a walk-around to check all lights.
- Front: Headlights (High/Low), Turn Signals, Clearance Lights.
- Sides: Marker lights, Turn signals.
- Rear: Tail lights, Brake lights, 4-Way Flashers.
- Reflectors: Clean and not broken (Red on rear, Amber on sides).
Test-day readiness check
Before scheduling, confirm that you can complete the same route without skipping sections, identify components on the actual type of vehicle you will use, explain component-specific defects, and demonstrate the in-cab checks in your state’s required order.
This page is a study checklist, not permission to use notes during the test. Whether any aid is allowed is determined by the testing agency.
Run the Pre-Trip Inspection diagnostic, record the sections you miss, and rehearse those components on the same vehicle type you will test in. The complete 1,500+ question library is available as a one-time $19.99 upgrade if you need continued practice.
Official references: Federal CDL skills standards, 49 CFR §383.113 and FMCSA pre-trip inspection skills-test information. Always use your state’s current CDL manual for the administered test.