Cruise Control Inhibited

WARNING: This page is about a different car, the 2006 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The engine control module (ECM) inhibits the cruise control operation when any of the following conditions exist:

A Cruise Control System DTC has been set.
The vehicle speed is less than 40.2 km/h (25 mph).
The vehicle speed is too high.
The vehicle is in PARK, REVERSE, NEUTRAL, or 1st gear.
The engine RPM is too low.
The engine RPM is too high.
The system voltage is not between 9-16 volts.
The Antilock Brake System (ABS)/Traction Control System (TCS) is active for more than 2 seconds.