2026 PennDOT CDL Pre-Trip Inspection Walkthrough

Use the complete transcript below to review the inspection language, revisit individual components or follow along with the video at your own pace. The transcript is provided as a learning aid. Applicants should rely on the current Pennsylvania Commercial Driver’s Manual and their examiner’s instructions for official testing requirements.

Video Chapters

• 00:00 Introduction and modernized CDL checklist
• 00:22 Cab inspection and safe start
• 00:48 Governor cut-out
• 01:12 Complete air-brake test
• 03:54 Dashboard lights and indicators
• 04:18 Emergency equipment
• 05:07 Windshield, mirrors and wipers
• 06:02 Heater, defroster and horns
• 06:46 Tractor and trailer parking-brake checks
• 07:36 Service-brake check
• 08:18 Exterior light check
• 08:43 Front and exterior inspection
• 09:05 Engine fluid levels
• 09:45 Hoses and steering components
• 10:13 Tires, rims and lug nuts
• 10:59 Suspension and brake components
• 11:31 Battery, fuel and DEF systems
• 12:05 Frame, air lines and electrical connections
• 12:49 Fifth wheel and coupling system
• 13:09 Landing gear and trailer inspection
• 13:55 Rear trailer inspection

Speaker: Jolyn Graham, CNS Driver Training Center
Video length: Approximately 14 minutes

Editor’s note: This transcript has been lightly edited for clarity, readability, and accurate CDL terminology. It follows the demonstration shown in the video and is not a substitute for the current Pennsylvania CDL manual, PennDOT instructions, or guidance from your CDL examiner.

00:00 — Introduction

Hi, my name is Jolyn Graham. I’m with CNS Driver Training Center, and today we’re going to talk about the modernized CDL test—specifically, the pre-trip vehicle inspection.

On your screen, you will see the driver’s CDL checklist. You can find this checklist in the CDL manual. You may bring the checklist with you for your test and check off the boxes as you inspect each item and complete your inspection.

All right, let’s get to it.

00:22 — Safe Start and Air-Brake Check

As the Class A CDL checklist states, we’re going to begin inside the cab with the air-brake check.

First, I will perform a safe start. If the truck has a manual transmission, I will make sure it is in neutral, press in the clutch, and start the truck.

00:48 — Governor Cut-Out

After the truck starts, I will build air pressure to the governor cut-out, which should occur between 120 and 140 psi. You can apply a little throttle to help the air pressure build faster.

My governor has cut out, so I will move to the second step of the air-brake check.

01:12 — Preparing for the Applied-Pressure Test

First, I will chock my wheels. If I am in a truck with an automatic transmission, I will exit the vehicle and place chocks at the wheels.

Because we are in a manual-transmission truck, we are going to place the vehicle in a low gear to simulate chocking the wheels. I will turn the truck off, turn the key back to the on position so the electrical system is active, and release both the tractor and trailer parking brakes.

01:47 — Applied-Pressure Air-Leak Test

Now I will press and hold the service brake for one minute. During that minute, I will make sure the system does not lose more than 4 psi. If you do not have a watch, ask your examiner to time the test.

After one minute, I have not lost more than 4 psi.

02:11 — Low-Air Warning Devices

For the third step, I will check the low-air warning devices. I will repeatedly press and release the brake pedal until the low-air warning devices activate.

I need to see a red warning light on the dashboard and hear a warning buzzer before the air pressure drops below 55 psi.

My low-air warning devices activated before the pressure dropped below 55 psi.

02:40 — Emergency Spring Brakes

For the fourth step, I will make sure the emergency spring brakes work properly. I will continue to fan the brakes until both the tractor and trailer parking-brake valves pop out, engaging the spring brakes.

The valves should pop out between 45 and 20 psi.

Both the tractor and trailer parking-brake valves have popped out. This indicates that the spring brakes, or emergency brakes, have activated and are working properly.

03:26 — Rebuilding Air Pressure

That completes my air-brake check. I will perform another safe start and rebuild the air pressure to the governor cut-out.

03:54 — Dashboard and Lighting Indicators

Next, I will check my lighting indicators. I will make sure the left turn signal, right turn signal, high-beam indicator, and four-way hazard indicator work properly.

I will also make sure the ABS and DEF indicator lights illuminate and then turn off, indicating that they are working properly. Both the ABS and DEF lights illuminated and turned off.

My left turn signal, right turn signal, and four-way hazard indicators are all working properly. I will now turn on my headlights and check the high-beam indicator. The blue light shows that the high-beam indicator is working properly.

04:18 — Emergency Equipment

Next, I will inspect my emergency equipment.

I will make sure there is a fire extinguisher inside the truck that is properly secured, fully charged, current, and ready for use.

I will verify that the truck has three red reflective triangles. They should be functional, free of cracks or damage, and ready to use in an emergency.

I will also make sure the truck has spare fuses. Typically, you should have a spare fuse for every major component that uses fuses, unless the vehicle is equipped with circuit breakers.

05:07 — Windshield and Mirrors

Next, I will inspect the windshield and traffic-monitoring devices.

The windshield is clean, clear, free of illegal stickers, and has no cracks or damage. The inspection sticker is current.

The traffic-monitoring devices—my mirrors—are clean, clear, properly adjusted for me as the driver, and are not cracked or broken.

05:31 — Windshield Wipers and Washer Fluid

Next, I will inspect the windshield wipers and washer-fluid system.

The windshield-wiper arms are not cracked, broken, or damaged. The wiper blades make contact with the windshield and are not ripped, torn, frayed, or damaged.

I will operate the washer-fluid system to make sure the fluid covers the windshield and the wiper blades clean the windshield evenly.

The windshield wipers are working properly. The washer fluid covers the windshield, and the blades remove it evenly.

06:02 — Heater and Defroster

Next, I will check the heater and defroster.

I will turn the system to the defrost setting and switch it on. I can feel air blowing onto the windshield, so the defroster is working properly.

I will then select the bi-level setting. I can feel air from the upper vents and at the floor, so the heater is working properly.

06:24 — Air Horn and City Horn

The final items I will check inside the cab are the horns. I will make sure both the air horn and city horn work properly.

My air horn is working properly, and my city horn is working properly.

06:46 — Tractor and Trailer Parking Brakes

Now that I have passed the air-brake check, I will perform a parking-brake check for both the tractor and trailer.

Starting with the tractor parking brake, I will release the trailer brake by pushing in the red valve. I will place the truck in low gear and slowly release the clutch until I feel a tug. The tractor should not move forward.

That was a good check. The tractor did not move.

I will now engage the trailer brake and release the tractor brake. With the truck in low gear, I will repeat the process by slowly releasing the clutch and tugging against the trailer brake to confirm that it holds.

The truck did not move, which means the trailer brake is working properly.

07:36 — Service-Brake Check

Next, I will perform a service-brake check. I will release both the tractor and trailer parking brakes, place the truck in gear, move forward at approximately 5 mph, and firmly apply the brakes.

The truck should come to a smooth, even stop without pulling to the left or right.

The truck did not pull to either side, which indicates that the brakes are working properly.

07:59 — Cab Inspection and Light Check

At this point, I inform the examiner that my cab inspection is complete. Once the examiner confirms, we move to the light check.

I ask the examiner to observe the front and sides of the tractor and trailer. I activate the right turn signal, left turn signal, four-way flashers, running lights, headlights, high beams, and clearance lights.

Then I ask the examiner to move to the rear of the vehicle. I repeat the checks for the left turn signal, right turn signal, four-way flashers, brake lights, and clearance lights.

Once everything is confirmed, we move outside and begin at the front of the tractor.

08:43 — Front Exterior Inspection

I will check that all lenses are clean, the proper color, secure, and not cracked, broken, or missing.

The truck should sit level from left to right and from front to back.

Looking under the truck, I will check for puddles or dripping fluids that could indicate a coolant or other fluid leak.

09:05 — Critical Fluid Levels

Next, I will inspect the critical fluid levels.

I will check the coolant reservoir and make sure the fluid is between the minimum and maximum marks.

I will check the engine oil with the dipstick. I will remove the dipstick, wipe it clean, reinsert it, and remove it again to confirm that the oil is within the proper operating range.

I will also inspect the power-steering fluid level using the sight glass or dipstick.

09:45 — Leaks, Hoses, and Steering Components

I will check for fluid and air leaks by looking for puddles, drips, or damaged hoses and listening for an audible hissing sound that could indicate an air leak.

Hoses should have no abrasions, cuts, bulges, or leaks.

Next, I will inspect the steering shaft, hoses, connections, steering box, steering-linkage joints, castle nuts, and cotter pins. Everything should be secure, undamaged, and free of leaks.

10:13 — Tires and Wheels

Next, I will inspect the tires. The tires must be the same size and type.

The front steering tires must have at least 4/32 inch of tread depth. All other tires must have at least 2/32 inch of tread depth. Tread depth should be checked with a tread-depth gauge.

I will inspect the tire sidewalls for abrasions, bulges, cuts, or other damage. I will inspect the valve stems and verify proper inflation with a tire-pressure gauge.

I will inspect the rims for damage. They should have no illegal welds or repairs, and the stud holes should not be excessively worn or elongated.

I will check the lug nuts for tightness and signs of looseness. There should be no missing lug nuts or studs. Rust trails or shiny threads on the studs may indicate looseness.

10:59 — Suspension and Brake Components

Next, I will inspect the suspension system, including the springs, mounts, U-bolts, and shock absorbers. Nothing should be damaged or leaking.

The U-bolts should be secure, and the four nuts holding them in place should be tight. All components should be in good condition, secure, and free of cracks or breaks.

Then I will inspect the brake lines and hoses for leaks or damage. I will also inspect the brake shoes and drums for contaminants such as oil, grease, or debris.

11:31 — Side Components, Battery, Fuel, and DEF

Moving along the side of the vehicle, I will inspect the lenses, reflectors, and mirrors. They should be clean, secure, and undamaged.

Next, I will inspect the battery and electrical system. The connections should be secure and free of corrosion. The batteries should be secured, the battery box should be attached to the frame, and the battery-box lid should close and latch properly.

I will inspect the DEF and fuel tanks to make sure they are securely mounted to the frame, undamaged, and not leaking. Both caps should be tight. The fuel lines should have no abrasions, bulges, cuts, or leaks.

12:05 — Frame, Air Lines, and Electrical Line

Next, I will inspect the tractor and trailer frames for damage and illegal holes or welds.

I will inspect the air lines between the tractor and trailer. They should be secure, undamaged, and not tangled or dragging on the catwalk or frame.

The hoses should be free of cuts and other damage. They should be securely connected to the tractor and trailer with glad hands. The glad hands should have rubber seals to help prevent air leaks.

Next, I will inspect the electrical line. It should be secured to both the tractor and trailer and locked in place by the safety locking tab. The line should not be cut, frayed, or burned, and there should be no exposed wires.

12:49 — Fifth Wheel and Coupling System

Now I will inspect the fifth wheel. It should be secure, properly lubricated, and free of damage.

I will inspect the kingpin, apron, and locking jaws to confirm a proper connection. There should be no gap between the trailer apron and the fifth-wheel skid plate.

I will also inspect the release arm and fifth-wheel sliding rails for proper positioning and security.

13:09 — Landing Gear and Trailer Components

Next, I will inspect the landing gear. It should be fully raised, secure, and undamaged.

Looking down the side of the trailer, I will make sure the DOT reflective tape is present and properly adhered.

I will inspect the trailer crossmembers for signs of damage and confirm that none are missing.

13:35 — Trailer Floor and Tandem Assembly

I will inspect the trailer floor for excessive holes, sagging, or signs of dry rot.

The tandem frame and sliding rails should be free of cracks or damage. The locking lever or valve should be in the locked position, and the sliding-rail locking pins should be extended through the holes.

13:55 — Side and Rear Inspection

Finally, I will move to the side and rear of the vehicle.

I will check all lenses and reflectors to make sure they are clean, secure, the proper color, and undamaged. I will also verify that the reflective tape is properly adhered to the rear of the vehicle.

14:12 — Conclusion

At this point, we have completed the modernized CDL pre-trip vehicle inspection. Now, let’s move on to backing.