Busting **** in my 97 XK8 today doing about 90. When I looked down to see how fast I was going I saw a LOW COOLANT message on display. After a few seconds it went off. I was kicking it at about 90. Is the cooolant something that can be checked, is there a LEVEL that it needs to be at?
Are these cars PRONE to throwing errant codes. It does it from time to time for the open hood when it AINT OPEN!

 

Remember, the open hood message can also mean convertible latch not closed also. I found that one the hard way once..drove me crazy...opening, closing the hood, over and over. Then looked up and latch wasnt down all the way. doh!

As for the coolant, yes...just like all cars, there is a resevoir (the call it an 'expansion tank' in jag terms) under the hood. It does have a full level, most likely, you were moving alot of coolant at that speed, and brought the level down...just top it off w/ extended use antifreeze (50/50) w/ distilled water. you'll be good. Now, if it comes on again in a month or two, there are a couple points to look for where leaks are common on these xks, but until that happens, don't worry about it now.