P0299 on GMC TERRAIN — Turbocharger/Supercharger A Underboost Condition

Q: "What does P0299 mean on a GMC TERRAIN?"

"P0299 indicates: Turbocharger/Supercharger A Underboost Condition. This is a fuel injection code. 3 GMC TERRAIN owners have reported this to NHTSA."

Q: "What are the most common causes of P0299 on GMC TERRAIN?"

"Based on 3 NHTSA reports, the most commonly cited components are: Engine, Power Train. These percentages are based on the component field in owner complaints."

Q: "Is P0299 serious on my GMC TERRAIN?"

"Of 3 NHTSA reports for this code on GMC TERRAIN, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my GMC TERRAIN shows P0299?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0299 Means on Your GMC TERRAIN

P0299 is a diagnostic trouble code indicating: Turbocharger/Supercharger A Underboost Condition. This code relates to the fuel injection system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

3 GMC TERRAIN owners have reported this issue to NHTSA across model years 2020-2022. Most reports come from the 2020, 2022 model years. The most commonly reported component is Engine (66.7% of reports).

Real GMC TERRAIN Owner Reports

Source: NHTSA Complaints Database

"This message concerns a persistent engine light that activates and generates engine code P0299, indicating an engine underboost issue. There have been several occasions where I am driving over 55mph on the highway and my 2020 Terrain SLT fails to pick up speed over 60mph in traffic."

— 2020 GMC TERRAIN owner · ENGINE · Filed 01/14/2025

"I just purchased this vehicle about 2 weeks ago, and was driving through the fog/cold weather and my check engine light came on. Went to O'Reillys and had them check the code."

— 2020 GMC TERRAIN owner · ENGINE · Filed 01/01/2023

"SUVs check engine light turned on and went into reduced power mode, it has been very cold for approximately a month. Code P0299."

— 2022 GMC TERRAIN owner · POWER TRAIN · Filed 01/29/2026

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

2

'20

1

'22

Common Causes on GMC TERRAIN

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 66.7%

POWER TRAIN 33.3%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0299 mean on a GMC TERRAIN? ▾

P0299 indicates: Turbocharger/Supercharger A Underboost Condition. This is a fuel injection code. 3 GMC TERRAIN owners have reported this to NHTSA.

What are the most common causes of P0299 on GMC TERRAIN? ▾

Based on 3 NHTSA reports, the most commonly cited components are: Engine, Power Train. These percentages are based on the component field in owner complaints.

Is P0299 serious on my GMC TERRAIN? ▾

Of 3 NHTSA reports for this code on GMC TERRAIN, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my GMC TERRAIN shows P0299? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.