I see your post was in March. I have a similar problem with a oi-MC control. I get 430 alarm for X axis. (sv overheat). I know it is not overheated. Sometimes i get the alarm right after power up.
I tried shorting the thermister contacts on the Bis4/4000 motor, but it didn't like that at all. Immediately got the 430 alarm without the usual 1 minute wait.
Did you find a way to bypass the alarm? Or otherwise fix it?