service engine soon on 1999 Cadillac Seville STS

why does my cadillac only turn on when service engine soon light is on..?

Asked by for the 1999 Cadillac Seville STS
1 answer
I'm not sure I understand this. The service engine soon light is the check engine light. You can read more about it here:

It means that there is a problem with your car that could definitely be serious enough to affect starting.