I have a 2007 Saturn Vue with +154k miles. I get it routinely serviced w/ oil changes and suggested maintenance at so many miles. My ABS light came on yesterday and when I hit the brakes, they started feeling like they were grinding the closer I got home. About a week ago,my check engine light started coming on for 30 secs and go off, but thought it was just the routine when starting vehicle. When I pulled into driveway, it was making a hissing type of sound after I turned it off. Went out a couple hours later and it's still doing it. I am unable to attach the mp4 file with the sound. Of course, this happened late Friday afternoon and my mechanic cannot look at it until Tuesday.

 

I don't know squat about the Vue, but if I hear a hissing sound, the first thing I'm looking for is a leak in the radiator or one of the hoses. Check your coolant level and see where it is. As for the brakes, it could be a wire connector that's loose or corroded or a tone ring on one of the wheels. You'll probably need your mechanic to look at that. IDK if you're mechanically inclined or not. Guessing not since you have a mechanic.

 

This sounds like two separate issues. The ABS light and grinding may be due to a failed bearing/sensor assembly. And the hissing is likely a cooling system issue, and you're hearing the pressure from the system releasing through the leak once the engine is shut off.

Let us know what your mechanic finds.

 

A thought occurs... It's possible there is a link between the brake light and the hissing, supposing the power brake booster is failing and leaking vacuum, being noticeable audible once the engine is shut off. However, if that were the case, you;d likely notice it being more difficult to press down the brake pdeal in order to get the car to stop. Just tossing it out there as a possibility.

 

I considered mentioning a leaking power check valve on the booster, but don't even know if they put them on Saturns. Anyone know for sure? But a leaking check valve should definitely affect the braking.

 

Indeed I believe that check valve is standard issue on today's brake boosters.
Hissing may be from the reservoir cap.

Post it on youtube and post the link here