[Achiyan]

completely topped off but light/message is steadily on. any ideas?

 

[TSS]

Likely a bad sensor - had that issue with another Gm vehicle (06 SRX).

 

[kingnutin]

I've had that several times from a bad sensor, they really don't handle contaminants well at all.

 

[Achiyan]

ok. so chances are is that its just a bad sensor then? now i know where to start.

 

[kingnutin]

It's the one plugged into the radiator underneath the filler neck, it's flat and square, plug comes out the bottom. Quite easy to change, pop off the little spring clip, and gently pry it out, they get stuck. You will lose a small amount of coolant.