connected but constant restarting when in car, bluetooth on

I have an AT+T Z432, very basic, phone. It started out working perfectly with my Subaru  [recent model, has Bluetooth connection stuff].

Then I had an iPad from work in my bag with me, and my own iPad... and the mobile phone suddenly began a cycle of restarting, connecting to BT and then restarting again, over and over and over. 

[I like to listen to my audio books on the iPad while I drive, thru my free Library subscription...] but even when I turned the iPads off, no change. I tried turning off their BT, no luck. I tried restarting the Z432, no luck. It does not matter if I have the mobile phone connected by cable, charging, or just sitting in the car... if the BT is on, it keeps restarting.  I do not know how to correct this.  The phone will not stay on long enough to do anything but let me start to make a phone call, then it clicks off.  My car is able to see the mobile phone and connects successfully.  I just can not get the phone to cease the restarting, when the BT is active, and I am outside in the car.

It has, however, done that same thing to me, outside of the car, once... when I was walking in the yard.

So, I do not know if the issue is with the phone or some setting? I appreciate assistance, if anyone knows how to fix this.

Also, this phone is non-data phone... just good old fashioned text/sms and phone calls.  And in the beginning, it did work perfectly with the car audio system.  now, however, it won't cooperate. I can make a call within my car as long as the BT is off, but that's wonky.