Engine-CodesGMC – C0299 GMC

C0299 GMC Code - Brake Booster Large Vacuum Leak Detected

Quick Answer

The C0299 GMC code indicates that a large vacuum leak has been detected in the brake booster system of the vehicle. Common causes include Damaged brake booster diaphragm, Loose or disconnected vacuum hoses, Faulty check valve in the vacuum line. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
C0299 GMC indicates Brake Booster Large Vacuum Leak Detected.
Common causes
Common causes include Damaged brake booster diaphragm, Loose or disconnected vacuum hoses, Faulty check valve in the vacuum line.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code C0299 GMC Description

The C0299 GMC code indicates that a large vacuum leak has been detected in the brake booster system of the vehicle. The brake booster is a critical component of the braking system that helps amplify the force applied to the brake pedal, making it easier for the driver to stop the vehicle. The vacuum leak in the brake booster can significantly impact the vehicle's performance and safety.

OBDII Code C0299 GMC - Brake Booster Large Vacuum Leak Detected
C0299 GMC Code - Brake Booster Large Vacuum Leak Detected

Common Causes of C0299 GMC

  1. Damaged brake booster diaphragm
  2. Loose or disconnected vacuum hoses
  3. Faulty check valve in the vacuum line
  4. Leaking brake booster seal
  5. Cracked or damaged brake booster housing

Symptoms of C0299 GMC

  1. Hard brake pedal feel
  2. Increased stopping distance
  3. Brake pedal sinking to the floor
  4. Illumination of the brake warning light on the dashboard

How to Fix C0299 GMC

  1. Inspect the brake booster system for any visible signs of damage, such as cracks or leaks.
  2. Test the vacuum hoses and check valve for proper function and tightness.
  3. Replace the brake booster diaphragm if it is found to be damaged.
  4. Repair or replace any faulty components in the brake booster system.
  5. Perform a vacuum test to ensure that the system is holding pressure properly.

Cost to Fix C0299 GMC

The typical repair costs for addressing a brake booster large vacuum leak can range from $200 to $600, including parts and labor. However, the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's advisable to check local rates for a more precise estimate.

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Information for Specific GMC Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C0299 GMC Code

1. What are the common symptoms of OBDII code C0299 Brake Booster Large Vacuum Leak Detected in a GMC vehicle?

- Common symptoms include a hissing noise when pressing the brake pedal, reduced braking performance, and the illumination of the check engine light.

2. What are the possible causes of OBDII code C0299 in a GMC, indicating a large vacuum leak in the brake booster system?

- Potential causes include a damaged brake booster diaphragm, disconnected or cracked vacuum hoses, or a faulty brake booster check valve.

3. How can I diagnose a large vacuum leak in the brake booster system triggering OBDII code C0299 in my GMC?

- You can visually inspect the vacuum hoses and connections for any signs of damage, listen for hissing sounds when pressing the brake pedal, and use a smoke machine to pinpoint the source of the leak.

4. Can a failing brake booster itself cause OBDII code C0299 to appear in a GMC?

- Yes, a failing brake booster with a damaged diaphragm can lead to a large vacuum leak, triggering the C0299 code in the GMC's onboard diagnostic system.

5. What are some repair tips for addressing OBDII code C0299 Brake Booster Large Vacuum Leak Detected in a GMC?

- Repair tips include replacing damaged vacuum hoses, checking and replacing the brake booster check valve if necessary, and ultimately replacing the brake booster if it is found to be faulty.

6. Is it safe to continue driving my GMC with OBDII code C0299 indicating a large vacuum leak in the brake booster system?

- It is not recommended to drive the vehicle with a large vacuum leak in the brake booster system, as it can compromise braking performance and safety. Immediate attention and repair are necessary.

7. Can a DIY enthusiast with basic automotive knowledge fix OBDII code C0299 related to a brake booster vacuum leak in a GMC?

- Depending on the extent of the issue, a DIY enthusiast with basic automotive knowledge may be able to address the problem by inspecting and replacing damaged vacuum hoses or the brake booster check valve. However, more complex repairs may require professional assistance.

8. How much can I expect to pay for repairing OBDII code C0299 Brake Booster Large Vacuum Leak Detected in a GMC at a mechanic or dealership?

- The cost of repairing OBDII code C0299 in a GMC can vary depending on the specific issue and the labor rates of the mechanic or dealership. It is recommended to obtain quotes from different service providers for comparison.

9. Will resetting the check engine light make OBDII code C0299 disappear temporarily in a GMC?

- Resetting the check engine light may temporarily make the code disappear, but if the underlying issue causing the large vacuum leak in the brake booster system is not addressed, the code is likely to reappear upon further driving.

10. Are there any preventive measures I can take to avoid OBDII code C0299 related to a brake booster vacuum leak in my GMC in the future?

- Regularly inspecting the brake booster system for any signs of wear or damage, promptly addressing any strange noises or brake performance issues, and following the manufacturer's recommended maintenance schedule can help prevent OBDII code C0299 from occurring.

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