Cadillac Repair: 99 Cadillac Deville - Stability Control System, coolant level, coolant leak

Question
My mother has a 99 Cad. Deville w/51K on a Northstar engine.  Just a little too late, she told us the "Check Coolant Level" message was showing up. We just had the engine replaced w/Northstar engine of the same make w/46/k ,due to an internal coolant leak.  At the same time, we replaced the battery,tie rods, had an alignment job & had the computer reset. The engine seems to run fine but the DIC scrolls a message that says "Stability Control System" that was not showing up before.  You can switch the car off or press the reset button and it goes away, but reappears a short time later.  Any ideas on what may be causing this? Is this something that needs to be addressed immediately to prevent another "major" repair?

Answer
The check coolant level message is most likely a faulty sensor.

The stability problem is also most likely a sensor problem also. Both are really nothing to get all excited about but will not cause and damage to the vehicle.

But they should be repaired in order to keep the check engine light from coming ON.