There is no way of adjusting the belt tension manually because the tensioner pulley automatically does it.
Spraying the belt with water is for diagnostic purposes only. If the squealing noise goes away briefly with the water then it is the belt making the noise.
As for the check engine light.
Most auto parts suppliers will scan your vehicle for free. Give the code(s) to me so I can assist you. Usually the compressor will not set a check engine light
If possible I would suggest a second option on your vehicle.
For squealing noises it is usually the belt, belt tension, or one of the pullies the belt rides on.
Saturday, May 31st, 2014 AT 8:47 AM