So my 97 Caravan seemed to be fine than the check engine light popped on and I noticed theres a strange rattling sound, sounds as if theres a rattle snake under my hood ! its coming from the left side near top pulley it sounds like. Belts seems fine though.
Anyone have this problem before ?

 

Your Service Engine Soon (SES) light is telling you there is a code stored in the engine computer. This could be a clue to your rattle. To get the code cycle the key from off to on (not start) three times leaving it on. Now count the flashes of the service engine soon light. This could be a clue to your rattle. All codes have two digits. A code 21 would be flash, flash, pause, flash. There will be a longer pause between each two digit code. Should finish with a code 55.

Could just be the typical pulley bearing "cricket" noise. Use a short length of hose cupped to your ear or a mechanics stethoscope ($10) to pinpoint the noise. Be careful around those moving parts.

 

I tried it out and the codes read 1 -2 , 2-1 , than 5 -5 . 6 -6 . thanks for your help