Yup. The computer performs a self-test on all of the circuits and sensors when you turn on the ignition switch. The warning light will be on for that seven seconds, then it will go out. The sensors will continue to be monitored while driving. If a problem is detected, the computer will shut the system down, set at least one diagnostic fault code in memory, and turn the warning light on. The air bag will not pop in a crash when the warning light is on.