Pre-Trip Vehicle Inspection
Domain 4: Pre-Trip Vehicle Inspection
This domain tests a complete, systematic walk-around. You must show you can inspect the engine compartment, lights, steering, suspension, brakes, tires, emergency equipment, and passenger compartment, and explain what you are checking.
Core rules
- Use a fixed sequence, such as driver’s area → engine compartment → lights → steering/suspension → brakes → tires → passenger compartment → emergency equipment.
- Check engine oil, coolant, power-steering fluid, washer fluid, belts, hoses, battery, and leaks.
- Check tire tread: at least 4/32 inch on front steer tires and 2/32 inch on other tires; look for cuts, bulges, and exposed cord.
- Test parking brake, service brake, horn, wipers, mirrors, and all lights.
- For a passenger vehicle, check emergency exits, fire extinguisher, first aid kit, seats, aisles, handrails, and roof hatches.
Worked example
At a front tire, check tread depth with a gauge, inspect sidewalls for cuts and bulges, check inflation, look for rust streaks around lug nuts, and confirm the wheel is not cracked. Then check the slack adjuster and brake hose. If a tire is below 4/32 inch on the steer axle, it fails - do not sign the inspection.
Traps that cost marks
Skipping the under-hood check; not testing the parking brake; missing an expired fire extinguisher; ignoring an emergency exit that will not open; and failing to recheck for leaks after starting the engine.