Why will my 2001 Acura MDX drive fine while cold but when it warms up it wont

What is your question?

It drives perfectly fine while cold and starts up fine. D5 light just started blinking and heat wont work..hasnt been started in about a month so i dnt know when D5 light started blinking

What makes this problem better or worse?

When engine warms up

How long has your 2001 Acura MDX had this problem?

3 months but wasnt driving