AutoCodes – Buick – C0299 Buick

C0299 Buick Code - Brake Booster Large Vacuum Leak Detected

Quick Answer

The brake booster vacuum sensor measures the vacuum in the brake booster assembly. Common causes include Vacuum leak at the brake booster, Faulty Brake Booster Vacuum Sensor, Brake Booster Vacuum Sensor harness is open or shorted. 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 Buick indicates Brake Booster Large Vacuum Leak Detected.
Common causes: Common causes include Vacuum leak at the brake booster, Faulty Brake Booster Vacuum Sensor, Brake Booster Vacuum Sensor harness is open or shorted.
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.

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Code Popularity 4,740

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 05, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0299 Buick Description

The brake booster vacuum sensor measures the vacuum in the brake booster assembly. The Electronic Brake Control Module (EBCM) supplies a 5 V reference and a low reference circuit to the brake booster vacuum sensor. The vacuum sensor supplies a voltage signal in relation to the pressure in the brake booster to the Electronic Brake Control Module. The Diagnostic Trouble Code (DTC) will be set when the Electronic Brake Control Module detected a too-low vacuum in the brake booster assembly.

OBDII Code C0299 Buick - Brake Booster Large Vacuum Leak Detected - AutoCodes.com — C0299 Buick Code - Brake Booster Large Vacuum Leak Detected

What does this mean?

What are the Possible Causes of the DTC C0299 Buick?

Vacuum leak at the brake booster
Faulty Brake Booster Vacuum Sensor
Brake Booster Vacuum Sensor harness is open or shorted
Brake Booster Vacuum Sensor circuit poor electrical connection
Faulty Electronic Brake Control Module (EBCM)

How to Fix the DTC C0299 Buick?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0299 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 Buick Code

1. What does the OBDII code C0299 on a Buick mean?

C0299 indicates that the electronic brake control module (EBCM) has detected a large vacuum leak in the brake booster system, which can affect braking performance.

2. What are the symptoms of a C0299 code on a Buick?

Common symptoms include a hard or stiff brake pedal, reduced braking performance, hissing noises near the brake booster, and the illumination of the ABS or brake warning light.

3. What causes the C0299 code to appear on a Buick?

The code can be caused by a damaged or leaking brake booster diaphragm, a cracked or disconnected vacuum hose, a faulty check valve, or insufficient engine vacuum levels.

4. Can I drive my Buick with the C0299 code?

Driving with this code is not recommended, as it can compromise braking performance, making it harder to stop the vehicle safely.

5. How do I diagnose a C0299 code on a Buick?

Start by inspecting the brake booster and vacuum hoses for visible damage or leaks. Use a vacuum gauge to test the vacuum level and check the brake booster check valve for proper operation.

6. How can I fix the C0299 code on my Buick?

Repairs may include replacing a damaged brake booster, repairing or replacing vacuum hoses, replacing the check valve, or addressing engine vacuum issues.

7. How much does it cost to repair a C0299 code on a Buick?

Costs vary depending on the issue. Replacing a vacuum hose or check valve may cost $50-$150, while replacing the brake booster can range from $300 to $700, including parts and labor.

8. Can a dirty engine air filter cause a C0299 code?

While unlikely, a severely clogged air filter can reduce engine vacuum levels, potentially contributing to the code. Inspect and replace the air filter if necessary.

9. Does the C0299 code affect the ABS system on a Buick?

Yes, the C0299 code can trigger the ABS warning light, as the EBCM relies on proper brake booster function for optimal braking system performance.

10. What tools are needed to troubleshoot a C0299 code on a Buick?

Common tools include a vacuum gauge, a scan tool to clear and monitor codes, and basic hand tools for inspecting and repairing vacuum hoses and other components.