Faulty transmission control valve can fail and cause rear wheels to lock up, increasing risk of crash, according to General Motors.

Due to the constant flow of air, the valve becomes clogged over time and needs cleaning. A clogged valve will result in several symptoms indicating that the idle air control valve is not functioning ...

At the center of the issue is a potential failure in the transmission control valve body, which manages hydraulic circuits for gear shifts. This failure can cause a momentary rear-wheel lock-up.

GM is covering the repair costs of transmission control valve problems for over a half-million full-size trucks and SUVs for 15 years or 150,000 miles.