- Based on 2025 ON commercial driver's licence manual
- Updated for April 2025
ON Air Brake Test 14
Ontario Commercial Air Brake Test 14 is your final frontier. With a spotlight on dual air systems, our 50-question exam prepares you to tackle every aspect of the official test. Make sure you're prepared by practicing with us.
- Perfect for first-time and renewal commercial applicants, and those adding endorsements
- Triple-checked for accuracy
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Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.
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What to expect on the official exam
50
questions
40
correct answers to pass
80
passing score
Our commitment to accuracy and quality in our practice tests
Explore our rigorous, multi-tiered verification process that ensures each question mirrors the official manual for unparalleled accuracy.
Written by Andrei Zakhareuski Updated over a week ago
At Tests.ca, we understand the importance of reliable and accurate practice tests to help you prepare for your driver's knowledge exam. That's why we've developed a meticulous process to create and continually update our practice questions, ensuring they reflect the most current driving laws and regulations.
Here's an inside look at how we maintain the highest quality in our practice tests.
Content Creation and Verification Process
- Alignment with Official Driving Handbooks:
Every question we develop is based on the most recent version of each province's official driving manual. Our team regularly monitors each province's official website for the latest updates to ensure our practice tests are always aligned with the most current information. - Community Feedback Integration:
We leverage feedback from our vast community of users to understand which topics are most frequently tested. This helps us focus on the areas that are most relevant and beneficial for your preparation. - Expert Content Creation:
Our in-house editor, Steven, who has extensive experience in driver education, crafts each question with precision. He conducts a thorough review of each question against the official manuals to ensure accuracy. - Rigorous Review Process:
Once Steven has finalized a set of questions, our team conducts a joint review session. This second level of scrutiny involves content accuracy, proofreading, and fact-checking to eliminate any errors. - User Feedback Mechanism:
After a question goes live on our site, we keep the lines of communication open. Each question features a feedback button, inviting users to report any issues or errors. This continuous feedback loop allows us to address and rectify any concerns promptly. - Responsive Updates:
In line with our commitment to accuracy, we quickly update our practice questions to reflect any changes in the provincial government manuals. Additionally, we update the free electronic copy of the state's driver's license manuals on our site, typically within a few days after the government publishes them.
Our thorough quality control process ensures that you have access to practice tests that are as accurate and up-to-date as possible. We believe in the power of well-prepared drivers and are dedicated to providing you with the best study tools to help you succeed on your driver's knowledge exam.
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List of questions (classic view)
- What is sourced to supply the spring parking brake control valve?
- If a failure occurs in the primary circuit, at what pressure does the spring parking brake control valve exhaust the remaining air in the secondary circuit?
- When the ABS begins to operate, your immediate reaction should be?
- Can tractors and trailers equipped with ABS be combined with those lacking ABS without affecting the ABS functionality?
- Which of these is not a part of the basic configuration of an ABS?
- What is Automatic Traction Control (ATC)?
- If the primary circuit fails and a brake application is made, where is control air from the foot valve directed to?
- In a tractor and trailer combination with spring parking brakes, what happens when the spring parking brake control valve is closed?
- Which system shares many the same sensing and control components with the automatic traction control (ATC) system?
- In a vehicle equipped with Automatic Traction Control (ATC), how is the driver alerted when wheel slip is detected?
- What does the ABS do when it detects a wheel locking up during a brake application?
- The spring parking brakes with a modulator valve perform how many functions?
- When a brake application is made and the system detects a wheel locking up, how does the ECU respond?
- Where can the system warning light for trailers with ABS typically be found?
- What best describes an anti-lock brake system (ABS)?
- Are old and new tractor and trailer systems interchangeable with respect to those with spring parking brakes?
- In a vehicle equipped with an air brake system with manual slack adjusters, can the brake pedal be pumped to compensate for brakes that are out of adjustment?
- In a vehicle equipped with Automatic Traction Control (ATC), what happens if wheel slip is detected while the vehicle's cruise control is set?
- As the air pressure drops below 85 psi, what happens to the spring parking brakes?
- How is electronic engine control activated?
- When does differential braking occur?
- If air in the primary circuit is lost, the spring-brake modulator valve allows the driver to still use the brake pedal to apply the brakes. Until when can brake applications be repeated?
- Does the air brake system remain the same even with the addition of ABS components?
- Is it possible for a trailer with a basic air brake system to be towed by a tractor with a dual air brake system?
- Which of the following typically causes brake failures?
- Select the incorrect steps when adjusting S-cam brakes with manual slack adjusters.
- What should you do at your first stop after adjusting the brakes?
- When doing a pre-trip inspection, at how many psi should the warning devices function?
- You can stay aware of the condition of your vehicle's braking system by doing all of these EXCEPT
- What is not a step to determine if an S-cam brake with manual or automatic slack adjusters needs adjustment?
- After two inches of push rod stroke, what happens to the force available at the push rod?
- When brakes are adjusted by slack adjusters, where do the shoes move?
- Identify the incorrect statement about the steps to determine if an S-cam brake with manual slack adjusters needs adjustment.
- When testing the low air pressure warning devices, why should you release the spring parking brake after pressure builds to 90 psi?
- After adjusting the manual slack adjuster, by what amount should the adjustment bolt be backed off?
- How long should the pre-trip air brake inspection take?
- Why is brake shoe adjustment necessary?
- Who should you consult regarding the adjustment procedure for various air disc brakes?
- If the S-cam brakes with automatic slack adjusters are severely out of adjustment, who should inspect them?
- What is not typically part of a brake test?
- During a leakage check, the pressure should not fall more than how many psi per minute?
- All of these can negatively affect a vehicle's braking ability EXCEPT
- When checking the S-cam brake adjustment with a manual slack adjuster, what should you ensure?
- What is the most reliable method to ensure your vehicle brakes are properly adjusted?
- What is not checked during an in-service check before a long or steep downgrade?
- When the brakes are out of adjustment, braking efficiency is reduced by all of these EXCEPT
- When is it recommended to adjust automatic slack adjusters by hand?
- How frequently should you check automatic slack adjusters?
- Who has the responsibility to ensure that the vehicle has safe, properly adjusted brakes?
- Identify the incorrect statement. During a pre-trip inspection, you should check the drive belt and pulleys for...
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