Step 1: Review the Vehicle's Paperwork

Start by reviewing the most recent vehicle inspection report. Motor carriers are required to fix anything noted in that report that affects safety, and to certify that the repair was made (or wasn't necessary). If defects were listed and confirmed as repaired or not needing repair, you'll need to sign off on the report yourself.

Step 2: Check the Engine Compartment

Before opening the hood, make sure the parking brakes are engaged and/or the wheels are chocked. Then, secure any loose items so nothing falls or breaks as you tilt the cab, raise the hood, or open the engine compartment. From there, check:

• Engine oil level
• Coolant level and the condition of the hoses
• Power steering fluid level and hose condition, if equipped
• Windshield washer fluid level
• Battery fluid level, connections, and mounting (the battery may be located elsewhere on some vehicles)
• Automatic transmission fluid level, which may require the engine to be running to check accurately
• Belt tightness and wear on components like the alternator, water pump, and air compressor
• Any leaks involving fuel, coolant, oil, power steering fluid, hydraulic fluid, or battery fluid
• Wiring insulation that appears cracked or worn

Once you've finished, close and secure the hood, cab, or engine compartment door.

Step 3: Start the Engine and Check Inside the Cab

Before starting the engine, confirm the parking brake is set and the gearshift is in neutral (or park, for an automatic). Start the engine and listen for anything unusual. If your vehicle has antilock brakes, watch the dashboard ABS light — it should light up briefly and then turn off. If it stays lit, the ABS system isn't functioning correctly. On a trailer, a malfunction shows up as a yellow light staying on at the left rear.

Next, look over your gauges:

• Oil pressure should rise to normal within just a few seconds of starting the engine
• Air pressure should climb from 50 to 90 psi within three minutes, continuing up to the governor cut-out point (commonly 120–140 psi, though this varies by vehicle)
• Ammeter and/or voltmeter readings should fall within the normal range
• Coolant temperature should begin rising gradually toward normal
• Engine oil temperature should also begin a gradual rise toward normal
• Warning lights and buzzers for oil, coolant, the charging circuit, and the antilock brake system should all shut off shortly after starting

You'll also want to test the condition of your controls, checking each for looseness, sticking, damage, or improper adjustment. This includes the steering wheel, clutch, accelerator, all brake controls (foot brake, trailer brake, parking brake, and retarder if equipped), transmission controls, the interaxle differential lock (if present), horn, windshield wiper and washer, and every light switch — headlights, dimmer, turn signals, four-way flashers, and parking/clearance/marker lights.

Finally, inspect your mirrors and windshield for cracks, dirt, illegal stickers, or anything else that could block your view, cleaning and adjusting as needed. Check that your emergency equipment is present — spare electrical fuses (unless your vehicle has circuit breakers), reflective warning triangles, and a properly charged fire extinguisher — along with optional extras like chains or tire-changing tools, a list of emergency phone numbers, and an accident-reporting kit. Lastly, confirm your seat belt mounts securely, adjusts properly, and shows no signs of fraying or damage.

Step 4: Shut Off the Engine and Test the Lights

Set the parking brake, turn off the engine, and take your keys with you — this prevents anyone from accidentally moving the vehicle while you're outside of it. Turn on your low-beam headlights and four-way flashers before stepping out to begin the walk-around.

Step 5: Perform the Walk-Around Inspection

This is the most detailed step, covering every side of the vehicle. Begin by confirming your low beams and both sets of four-way flashers are working from the front of the vehicle, then check that your high beams engage properly using the dimmer switch. Turn off the headlights and flashers, switch on your parking, clearance, side-marker, and identification lights, then turn on the right turn signal to begin your walk-around.

As you make your way around the vehicle, clean every light, reflector, and window you pass, and check the following areas:

• Left front side: Clean door glass, properly working door latches, and a thorough check of the left front wheel (rim and stud condition, tire inflation and condition, lug nut tightness, hub oil level), suspension (springs, hangers, shackles, u-bolts, shocks), and brake (drum or disc condition, hose condition).
• Front of the vehicle: Axle condition, steering system components (checking for looseness by hand), windshield condition and wiper function, and front lights and reflectors for proper color and operation.
• Right side: The same checks performed on the left front, plus the cab safety locks (on cab-over-engine designs), fuel tank security and fuel level, and visible signs of leaks from the engine, transmission, or exhaust system. You'll also check the frame, wiring, spare tire mounting, and cargo securement on this side.
• Right rear: Wheel and rim condition, tire type and match, tire condition, wheel bearing seals, suspension components, brake adjustment and condition, and side lights and reflectors.
• Rear of the vehicle: Rear lights, reflectors, and taillights; license plate condition and mounting; splash guards; and cargo security, including tailboards, end gates, tarps, and rear door latches.
• Left side: The same items checked on the right rear and right side, plus the battery box and battery condition, if not located in the engine compartment.

Step 6: Test the Signal Lights

Get back in the cab, turn off all lights, then activate your stop lights (either by applying the trailer hand brake or having a helper press the brake pedal) and your left turn signal. Step back out to confirm the left front turn signal and left rear turn signal and stop lights are all working and showing the correct color. Once you're back inside, turn off any lights you won't need while driving, gather your required paperwork, secure loose items in the cab, and restart the engine.

Step 7: Start the Engine and Run Final Checks

If your vehicle uses hydraulic brakes, pump the brake pedal three times, then apply firm, steady pressure for five seconds. The pedal shouldn't move — if it does, you may have a leak or another issue that needs to be resolved before driving. Vehicles with air brakes require a different check, covered elsewhere in the manual.

To test your parking brake, fasten your seat belt, set the parking brake, release the trailer's parking brake (if applicable), shift into a low gear, and gently pull forward against the parking brake to confirm it holds. Repeat the process for the trailer's parking brake if your vehicle is pulling one. If the brake doesn't hold, the vehicle isn't safe to drive.

Finally, test your service brakes by driving roughly five miles per hour and applying firm pressure to the brake pedal. Pulling to one side, or any unusual feel or delay in stopping, can signal a brake problem that needs to be addressed before you go any further.