California CDL Air Brakes Practice Test (CA) 2

5 out of 5 (248 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Get ready to ace your commercial driver's license (CDL) air brakes endorsement with our thorough California Air Brakes practice test. This second installment in our series of CDL practice tests is designed to provide you with the most comprehensive preparation possible. With 20 multiple-choice questions covering crucial topics like components, operation, safety inspections, and stopping distance calculations, this test ensures you're well-versed in every aspect of air brake systems. Our California DMV practice test includes real-life driving scenarios to enhance your understanding and application of air brake knowledge in practical situations. For instance, you'll learn about dual air brake systems, which are critical for maintaining safety by providing a backup in case one system fails. This real-world focus not only helps you pass the written test but also prepares you for the daily realities of driving in California's diverse and challenging road environments. California is known for its bustling highways, scenic coastal routes, and varying weather conditions, all of which demand a thorough understanding of your vehicle's braking systems. Our online permit practice test is regularly updated to reflect the latest driving laws and regulations, ensuring that you are studying the most current and relevant information. As of 2026, we've incorporated the latest updates to keep you ahead of the curve. To pass this test, you'll need to correctly answer at least 16 out of 20 questions. This rigorous standard is designed to mirror the actual CDL test, ensuring you're fully prepared. Remember, this endorsement-specific test is part of a broader CDL preparation, which includes the general knowledge test. If you need to brush up on general driving laws and regulations, we offer comprehensive prep tests for that too. Prepare yourself to tackle California's roads with confidence. Our DMV practice permit test not only equips you with the knowledge to pass your CDL air brakes endorsement but also fosters safer driving habits, crucial for navigating the state's busy freeways and scenic byways. Study with us, and ensure you're ready for both the test and the practical demands of commercial driving in California.
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Sample California Air Brakes Test Questions

Question 1

During an applied air-leakage test, what is the usual governor cut-out range unless the manufacturer specifies otherwise?

  1. A 80–100 psi
  2. B 100–115 psi
  3. C 120–140 psi
  4. D 150–170 psi

Correct answer: C – 120–140 psi

The California Commercial Driver Handbook begins the applied leakage test with the engine running and pressure built to governor cut-out. The usual cut-out range is 120–140 psi, although the vehicle manufacturer may specify another level. After cut-out occurs, the engine is shut off and the fully applied brake is held for the leakage measurement.

Source: California Commercial Driver Handbook — § 5.3.3, “1. Applied Leakage Test (1-minute hold)”

Question 2

Where is the ABS malfunction lamp located on a tractor, truck, or bus equipped with ABS?

  1. A A red lamp on the instrument panel
  2. B A yellow lamp on the instrument panel
  3. C A red lamp on the vehicle’s left side
  4. D A yellow lamp on the vehicle’s right side

Correct answer: B – A yellow lamp on the instrument panel

Tractors, trucks, and buses equipped with ABS have a yellow malfunction lamp on the instrument panel. The California handbook distinguishes this from a trailer’s yellow ABS lamp, which is located on the trailer’s left side near the front or rear corner. A lamp that stays on after its bulb check may indicate loss of ABS control at one or more wheels.

Source: California Commercial Driver Handbook — § 5.1.16, “Anti-lock Braking Systems”

Question 3

Why is repeated on-and-off service braking a poor way to control speed on a long downgrade?

  1. A It reduces air use and brake temperature
  2. B It keeps the linings cool without lowering pressure
  3. C It can overheat and fade the brakes while wasting reservoir air
  4. D It increases the compressor’s cut-out pressure

Correct answer: C – It can overheat and fade the brakes while wasting reservoir air

Repeated service-brake use can create excessive heat, resulting in brake fade and reduced braking force. Releasing the brake pedal also exhausts compressed air from the system. Unnecessary applications and releases can use air faster than the compressor replaces it. Drivers should select the proper low gear and use service brakes only as a supplement on a long downgrade.

Source: California Commercial Driver Handbook — § 5.1.7, “The Brake Pedal”, California Commercial Driver Handbook — § 5.4.5, “Brake Fading or Failure”

Question 4

The low-air-pressure warning activates while you are driving. What should you do?

  1. A Bring the vehicle to a safe stop and park as soon as possible
  2. B Continue until the spring brakes apply automatically

Correct answer: A – Bring the vehicle to a safe stop and park as soon as possible

A low-air warning may indicate a leak or another loss of system pressure. Stop and safely park while enough reservoir air remains for controlled braking with the foot brake. Spring brakes generally begin applying when pressure falls into the 20–45 psi range, and waiting for that automatic application can result in a long stop or a skid.

Source: California Commercial Driver Handbook — § 5.4.7, “Low Air Pressure”

Question 5

Under normal brake conditions, when should an air-brake vehicle’s parking brakes be applied?

  1. A Only during vehicle inspections
  2. B Whenever the vehicle is parked
  3. C Only when parked on a grade
  4. D While slowing during normal driving

Correct answer: B – Whenever the vehicle is parked

Use the parking brakes whenever you park under normal conditions. The California handbook provides exceptions when the brakes are extremely hot or are very wet in freezing temperatures; wheel chocks should then be used on a level surface until conditions are corrected. Never leave the vehicle unattended without applying the parking brakes or properly chocking the wheels.

Source: California Commercial Driver Handbook — § 5.4.8, “Parking Brakes”

Question 6

On a long or steep downgrade, service brakes should supplement the engine’s braking effect rather than replace it.

  1. A True
  2. B False

Correct answer: A – True

Engine braking should provide the primary speed control on a long or steep downgrade. After selecting the correct low gear, apply the service brakes firmly enough to produce a definite slowdown, then release them after reducing speed by about 5 mph. This technique limits continuous brake use and helps prevent excessive heat and brake fade.

Source: California Commercial Driver Handbook — § 5.4.6, “Proper Braking Technique”

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