In addition, have the mechanic check the battery, alternator, drive belt and componets also the charging 'system'. The trouble code(s) may prompt these checks anyway as the computer controls the alt voltage output. Which for some reason it seems, is not enough!!
when I start my car I hear a wining sound , it gets louder when I turn on lights,radio , fan , all at one time to ckeck electrical , then when I apply the gas pedal , motor gets gets sluggish, car is in park when I do all this.