Pre-Trip Inspection CDL Study Guide & Practice Questions - 2026-2027 | Commercial Driver Prep
Headlight/Front Reflectors not cracked or damaged and working properly
First Thing! chock the wheels!!!
Fender Mirrors properly mounted & secured, not cracked or damaged, clean and clear.
Under The Cab no water, oil, fuel leaks, loose wires.
Leaning caused by suspension problems, shifted load, or flat tire.
Electrical Wires/Hoses/Lines not cracked, damaged or leaking; no cuts or frays/wire housing is in good condition
Frame not cracked, bent, welds or drill holes
Alternator properly mounted & secured, no bolts missing, belt driven, belt should not have cuts
or frays, no more than 3/4" free play at center of belt
Water Pump properly mounted & secured, not cracked, damaged or leaking, belt driven, the belt
should not have cuts or frays, no more than 3/4" free play at center of the belt
, Pre-Trip Inspection CDL Study Guide & Practice Questions - 2026-2027 | Commercial Driver Prep
Oil Level proper level: check by pulling out the dipstick and wipe it off then put it back in,
check it again.
Radiator Coolant properly mounted and secure, proper level & not cracked, damaged or leaking &
cap is secure, can see coolant level through sight glass
Air Compressor properly mounted & secured, not cracked, damaged or leaking, gear driven
1. Air Leakage Test with the air pressure built up to governor cutoff (120-140 PSI range), place the truck
in neutral. turn off the engine (turn key on but do not start truck), & push in both
parking brakes. fully apply the foot brake, wait until after the initial pressure
drops(start timer), it should not lose more than 4 PSI in one minute (in a
combination vehicle).
2. Low Pressure Warning Test step on & off brakes. the low-pressure warning light & buzzer should come on
before the tank falls below 60PSI.
3. Spring Brake Test continue to step on & off brakes until the spring brakes pop out approximately at 40
PSI. The Trailer Valve (RED) first, followed by the Tractor Valve (YELLOW) or both
at the same time. NEVER the Tractor Valve (YELLOW) first.
4. Air Gauge Test start engine. with the engine at operating rpms (1200-1500), the pressure should
build from 85 to 100 PSI within 45 seconds. continue to build air pressure. the
governor cut out should be 120 to 140 PSI.
5. Parking Brake Test trailer valve (RED) in and tractor valve (Yellow) out, put truck in gear & give a gentle
tug (test tractor brakes). Trailer Valve (RED) out and tractor valve (YELLOW) in,
give a gentle tug (test trailer brakes).
6. Service Brake Test with truck in low gear, push both brakes (RED & YELLOW in). while holding the
steering wheel gently, pull ahead approximately at 5 MPH & apply the service
brakes. Check to see if there is any pulling to either side & that it stops when the
brake is applied.
Power Steering Pump properly mounted & secured, not cracked or damaged, leaking/ it's gear driven.
Power Steering Hoses & Reservoir properly mounted & secured, not cracked, damaged or leaking/ at proper level.
Power Steering Gear Box properly mounted and secured, not cracked, damaged, leaking
Steering Linkage/Shaft not bent, damaged and no missing nuts or cotter pins.
Headlight/Front Reflectors not cracked or damaged and working properly
First Thing! chock the wheels!!!
Fender Mirrors properly mounted & secured, not cracked or damaged, clean and clear.
Under The Cab no water, oil, fuel leaks, loose wires.
Leaning caused by suspension problems, shifted load, or flat tire.
Electrical Wires/Hoses/Lines not cracked, damaged or leaking; no cuts or frays/wire housing is in good condition
Frame not cracked, bent, welds or drill holes
Alternator properly mounted & secured, no bolts missing, belt driven, belt should not have cuts
or frays, no more than 3/4" free play at center of belt
Water Pump properly mounted & secured, not cracked, damaged or leaking, belt driven, the belt
should not have cuts or frays, no more than 3/4" free play at center of the belt
, Pre-Trip Inspection CDL Study Guide & Practice Questions - 2026-2027 | Commercial Driver Prep
Oil Level proper level: check by pulling out the dipstick and wipe it off then put it back in,
check it again.
Radiator Coolant properly mounted and secure, proper level & not cracked, damaged or leaking &
cap is secure, can see coolant level through sight glass
Air Compressor properly mounted & secured, not cracked, damaged or leaking, gear driven
1. Air Leakage Test with the air pressure built up to governor cutoff (120-140 PSI range), place the truck
in neutral. turn off the engine (turn key on but do not start truck), & push in both
parking brakes. fully apply the foot brake, wait until after the initial pressure
drops(start timer), it should not lose more than 4 PSI in one minute (in a
combination vehicle).
2. Low Pressure Warning Test step on & off brakes. the low-pressure warning light & buzzer should come on
before the tank falls below 60PSI.
3. Spring Brake Test continue to step on & off brakes until the spring brakes pop out approximately at 40
PSI. The Trailer Valve (RED) first, followed by the Tractor Valve (YELLOW) or both
at the same time. NEVER the Tractor Valve (YELLOW) first.
4. Air Gauge Test start engine. with the engine at operating rpms (1200-1500), the pressure should
build from 85 to 100 PSI within 45 seconds. continue to build air pressure. the
governor cut out should be 120 to 140 PSI.
5. Parking Brake Test trailer valve (RED) in and tractor valve (Yellow) out, put truck in gear & give a gentle
tug (test tractor brakes). Trailer Valve (RED) out and tractor valve (YELLOW) in,
give a gentle tug (test trailer brakes).
6. Service Brake Test with truck in low gear, push both brakes (RED & YELLOW in). while holding the
steering wheel gently, pull ahead approximately at 5 MPH & apply the service
brakes. Check to see if there is any pulling to either side & that it stops when the
brake is applied.
Power Steering Pump properly mounted & secured, not cracked or damaged, leaking/ it's gear driven.
Power Steering Hoses & Reservoir properly mounted & secured, not cracked, damaged or leaking/ at proper level.
Power Steering Gear Box properly mounted and secured, not cracked, damaged, leaking
Steering Linkage/Shaft not bent, damaged and no missing nuts or cotter pins.
