Engine Light

The service engine light in my '03 C1500 has recently been illuminating my life. Can I access the code without a code reader? I remember having an '88 Cavalier that I could stick a paper clip into 2 certain slots in the connector and count the flashes. Is that sort of thing possible with my truck?

What code # flashes on the dash?????

go to a autozone or similar store and they usually read it for free and tell you what it is