AutoCodes – GMC – P0299 2014 GMC Sierra

P0299 2014 GMC Sierra Code - Engine Underboost

Quick Answer

The Engine Control Module (ECM) uses the Manifold Absolute Pressure (MAP) sensor input and turbocharger actuator output to control the amount of engine induction system boost pressure. Common causes include Faulty Turbocharger Vane Position Actuator, Air leaks between the turbocharger and the intake air flow valve, Airflow restrictions in air ducts or air filter. 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: P0299 2014 GMC Sierra indicates Engine Underboost.
Common causes: Common causes include Faulty Turbocharger Vane Position Actuator, Air leaks between the turbocharger and the intake air flow valve, Airflow restrictions in air ducts or air filter.
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 249

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 Jun 09, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0299 2014 GMC Sierra Description

The Engine Control Module (ECM) uses the Manifold Absolute Pressure (MAP) sensor input and turbocharger actuator output to control the amount of engine induction system boost pressure. The ECM calculates a desired boost pressure value and monitors the actual boost pressure. If the difference between the actual boost pressure and the desired boost pressure is less than or greater than a calibrated threshold level, the ECM detects that the amount of detected boost pressure is out of range. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the difference between the actual boost pressure and the desired boost pressure in the intake manifold is less than the expected range for 12.5 s. The 12.5 s time is not continuous but cumulative. The timer may sum up a heavy load condition obtained during different maneuvers.

OBDII Code P0299 2014 GMC Sierra - Engine Underboost - AutoCodes.com — P0299 2014 GMC Sierra Code - Engine Underboost

What does this mean?

What are the Possible Causes of the DTC P0299 2014 GMC Sierra?

Faulty Turbocharger Vane Position Actuator
Air leaks between the turbocharger and the intake air flow valve
Airflow restrictions in air ducts or air filter
Ice or debris in the induction system
Leaks at the Positive Crankcase Ventilation (PCV) system
Faulty Turbocharger

How to Fix the DTC P0299 2014 GMC Sierra?

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 P0299 2014 GMC Sierra 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 P0299 2014 GMC Sierra Code

1. What does the OBDII code P0299 mean on a 2014 GMC Sierra?

P0299 indicates "Turbocharger/Supercharger A Underboost Condition," meaning the engine is not receiving the expected boost pressure from the turbocharger or supercharger.

2. What are the symptoms of code P0299 on a 2014 GMC Sierra?

Common symptoms include reduced engine power, poor acceleration, increased fuel consumption, black smoke from the exhaust, and the check engine light being illuminated.

3. What causes code P0299 on a 2014 GMC Sierra?

Potential causes include a faulty turbocharger, a damaged wastegate, vacuum leaks, clogged or damaged intercooler hoses, a malfunctioning boost pressure sensor, or restricted exhaust flow.

4. Can a dirty air filter cause the P0299 code on a 2014 GMC Sierra?

Yes, a clogged or dirty air filter can restrict airflow to the turbocharger, potentially causing an underboost condition.

5. Is it safe to drive with a P0299 code on a 2014 GMC Sierra?

Driving with a P0299 code is not recommended as it can lead to further engine damage, reduced performance, and poor fuel economy.

6. How do I diagnose the P0299 code on my 2014 GMC Sierra?

Start by inspecting the turbocharger, hoses, and intercooler for damage or leaks. Check the wastegate and boost pressure sensor for proper operation. A scan tool with live data can help monitor boost pressure levels.

7. Can a faulty wastegate actuator trigger the P0299 code on a 2014 GMC Sierra?

Yes, a stuck or malfunctioning wastegate actuator can cause boost pressure to drop, triggering the P0299 underboost code.

8. How much does it cost to fix the P0299 code on a 2014 GMC Sierra?

Repair costs vary depending on the cause. Simple fixes, like replacing hoses or repairing leaks, may cost $100-$300, while turbocharger replacement can exceed $1,000.

9. Can a bad exhaust system cause the P0299 code on a 2014 GMC Sierra?

Yes, a clogged catalytic converter or restricted exhaust system can reduce airflow, leading to an underboost condition and triggering the P0299 code.

10. How do I prevent the P0299 code on my 2014 GMC Sierra?

Regular maintenance, including cleaning or replacing the air filter, inspecting turbo components, and addressing exhaust system issues promptly, can help prevent this code from occurring.