It keeps flashing 4 times and it says that it is an open temperaure limit circuit what does this mean? It is a trane xl80

Your limit has been triggered by higher temperatures in the furnace than normal. This is a safety device. Look for a manual reset red button on the limit. If none there you might have to replace the control.

Since it went off on a safety device it might be wise for you to call a HVAC contractor since there could be other problems with your unit that caused this to happen.