US launches probe into nearly 1 million GM vehicles over engine issues

US safety regulators have launched a major investigation into approximately one million General Motors trucks and SUVs following a surge of complaints about engine failures. The National Highway Traffic Safety Administration (NHTSA) is examining 997,743 GM vehicles manufactured between 2021 and 2026, all equipped with the L87 engine.

The models under scrutiny include popular vehicles such as the Cadillac Escalade, Chevrolet Silverado 1500, and GMC Yukon, along with other trucks and SUVs from the GM group. The NHTSA has received 499 complaints detailing engine malfunctions that occurred even after vehicles were serviced under a recall issued last year.

General Motors had previously issued a recall in 2025 for vehicles with the L87 engine, attempting to preemptively address potential failures, which the company attributed to a supplier issue. This new investigation by the NHTSA will specifically concentrate on the recurring problems that have emerged post-repair and the efficacy of the solutions provided by the manufacturer.

While the authority has not yet determined if a new recall is warranted, the ongoing investigation could compel General Motors to implement further measures for the affected vehicles. The outcome will be crucial in assessing the long-term reliability and safety of these widely used GM models.