Why does the Bluetooth on my phone turn my car radio off?

[HuckleberryGin]

I got a new phone a few weeks ago (a Huawei p9). My previous HTC and Dh's iPhone all connect perfectly to my car's Bluetooth.

My new phone connects, but after a few minutes the whole radio console turns off. Can't be manually turned on. It sometimes comes back on itself and then off again. If I turn the Bluetooth off on my phone, no issue.

I have tried googling, it's driving me mad!