2002 Ford Windstar battery noise

[colucp]

2002 Ford Windstar:
Whenever I disconnect the battery and then reconnect it, I get this hum that sounds like the CD player preparing to play a CD. There is no CD in the player. It last for about 30 seconds and then stops. Afterwards, my check engine light comes on and stay on until I have the mechanic reset the alarm. The battery is new. My meter shows that the battery is giving out enough volts. It annoys me to have the check engine light on all of the time. I'd rather it be off so it can report if something else goes wrong with the engine. Anyone else have this problem?

[12Ounce]

So go to AutoZone, or the like, and have them do the free check-engine-light-code scan. Its likely that you have something actually wrong ... not just a worrisome light.