false temp alarm

[harrywalpole]

have a df 70 (2001 vintage). I am getting the following alarm:
the engine beeps for 1 1/2 secs every 7 secs with the temp lite on.
It does this on start up engine cold. I get a good stream,
i removed the thermostat, same. I run the engine and get no overheating.
No clue !