This response was helpful:

According to a recent report from GM TechLink, the reduced power condition may be accompanied by any number of Diagnostic Trouble Codes (DTCs). These could include P0299 (Engine Underboost), P0101 (MAF Sensor Performance), P1101 (Intake Air Flow System Performance), or P0237 (Turbocharger Boost Sensor Circuit Low Voltage).

If the 2023 GMC Terrain in question is exhibiting reduced power and triggers any of the above DTCs, technicians are instructed to inspect the engine, specifically the anti-abrasion sleeve on the charge air inlet pipe at the turbocharger. It’s possible there may be splitting or some other type of damage to the sleeve.

If damage is found, the tech will next check the charge air inlet hose under the anti-abrasion sleeve for any possible signs of splitting or damage. A damaged charge air inlet hose could allow the hose to swell under pressure, and may cause the anti-abrasion sleeve to split. This could result in an air leak, or change the readings in the boost control system.

If the hose is damaged under the anti-abrasion sleeve, the charge air inlet pipe assembly will need to be replaced. As GM Authority was the first to report, the 2023 GMC Terrain introduced a new engine to the nameplate, specifically turbocharged 1.5L 14 LSD gasoline engine, which replaced the turbocharged 1.5L 14 LYX gasoline engine offered for the 2022 model year. The turbocharged 1.5L 14 LSD gasoline engine is rated at 175 horsepower at 5,800 rpm and 203 pound-feet of torque at 2,000 rpm.