Funny story time...How old are these vehicles? Pretty much anything that can disable the cruise will have the Engine malfunction light come on
Wife took her Chevy HHR to a fancy hotel with valet parking. The valet, apparently (and out of sight), slammed it from reverse into drive while rolling backwards at a decent speed. Chevy decided to set a code, but without a MIL, and it disabled the cruise control even several key cycles later!
I cleared this mystery hidden code with my scanner and CC started working again.