Question 1
Ok drove my s60 for the first time in the snow and when pressing the brake, the car will slide and my brake pedal will vibrate/shake. also can not really turn or come to a complete stop when this happens. Never drove a car that has done this but im guessing its abs?

Queston 2... my check engine came on, and i have no idea why(hoping its just a loose gas cap) but can i take it to any shop to get the codes read or do i need a special obdII volvo scanner. Are they cheap to buy?IPD ,VIDA

 

any scanner will be able to view the codes, it's required by law that the car manufactures give access to engine and emissions data.

And yes the vibration of the pedal is the ABS system working, and I would guess the reason you can't turn is because it's just too slippery.

 

When I turn the car on, the check engine light will flash about 5 times then stays solid. is that normal or does the flashing mean something serious? Happens every time i start car..

 

Could be a misfire from worn plugs, or bad coils, get it fixed asap, or you could be looking at a new catalytic converter soon, and that's not cheap.

 

Only did so in the snow? So basically the abs is not working and the wheel locks or the brake pads are worn to the metal. Inspect abs wiring at the wheels, and brake discs/pads for wear/rust pits