CDL Guide - 8 min read
CDL Pre-Trip Inspection Checklist: What Examiners Look For
Master the CDL pre-trip inspection with this complete checklist covering every component examiners test you on.
The pre-trip inspection is the first part of your CDL skills test — and the part most students fail. Examiners want to see that you can systematically inspect a commercial vehicle and identify safety issues. Here's exactly what to cover.
Engine Compartment
- Oil level (dipstick between min/max)
- Coolant level (in reservoir, no leaks)
- Power steering fluid level
- Belts and hoses (no cracks, fraying, or leaks)
- Air compressor (connected, not leaking)
- Alternator (mounted, wires connected)
- Water pump (no leaks)
Cab / Brake Check
- Parking brake holds against gentle throttle
- Air pressure builds to governor cut-out (120-140 psi)
- Air brake leak test: with brakes applied, pressure drop less than 3 psi/min (single) or 4 psi/min (combination)
- Low air pressure warning activates (typically 55-60 psi)
- Spring brakes engage (20-45 psi)
- All gauges working (oil, temp, voltage, air)
- Steering wheel play (no more than 10 degrees)
- Windshield (no cracks in wiper area), wipers work
- Mirrors adjusted, clean
- Horn works
- Seatbelt works
- Emergency equipment: fire extinguisher (charged), reflective triangles, spare fuses
Walk-Around: Driver Side
- Door closes securely, hinges good
- Fuel tank (secure, cap on, no leaks)
- DEF tank (if equipped)
- Front tire: tread depth 4/32" min, no cuts/bulges, properly inflated, lug nuts tight
- Wheel seal (no leaks)
- Suspension (springs, mounts, shock absorbers)
- Brake components: drum, lining, hoses, slack adjuster (less than 1" play)
Front of Vehicle
- Headlights (low and high beam)
- Turn signals
- Clearance lights
- Bumper (secure, no damage)
- License plate (visible, current)
Passenger Side + Rear
Repeat the same tire, suspension, and brake checks for all axles on the passenger side. At the rear, check:
- Tail lights, brake lights, turn signals
- Reflective tape (visible, intact)
- Mud flaps (present, not dragging)
- Cargo doors (secure, latched)
Coupling System (Combination Vehicles)
- Fifth wheel: locked, no gap between apron and plate
- Kingpin (engaged in fifth wheel jaws)
- Air and electrical lines (connected, not dragging, no leaks)
- Landing gear (raised, crank handle stored)
- Trailer frame (no cracks)
Tips for Passing
- Use a consistent route — always go in the same order so you don't skip anything
- Talk out loud — explain what you're checking and why to the examiner
- Touch components — physically touch or point to each item
- Practice at least 10 times before your test