Why is my chevy tahoe check engine light on?

The Chevy Tahoe's "check engine" light indicates onboard diagnostics has detected an exhaust leak, mIS Fire or engine timing issue and should be serviced promptly. The warning could be triggered by a loose gas cap or a more serious issue like large amounts of unburned fuel being dumped into the exhauSTSystem. This scenario can elevate to overheating and catalytic converter failure. In other circumstances a faulty spark plug could be causing the light to flash and while this is not considered emergent, should be replaced soon. O2 sensor failure can also trigger the "check engine" indicator as well as a dying battery or alternator. MA service center can hook up an OBDII scanner to help diagnose the problem.