I'd say check your battery saving settings. Make sure Bluetooth is on and not sleeping.
I know it doesn't mention Bluetooth specifically, but it was a standard for power saving settings in the past.
Does your phone have Bluetooth connectivity issues with any other devices?
Try testing it with someone else's phone to narrow down if it's the phone or the head unit.
What year is your Tacoma?
Sometimes with phone technology advancing so quickly, Bluetooth version might be newer than the head unit.
Happened to me before and it was not backwards compatible 100%. Some features worked, but just wasn't reliable.
Next:
Factory reset the head unit.
If that doesn't help, wipe out your paired Bluetooth devices.
Wipe cache and data if there is any within Bluetooth Settings.
Not sure if Bluetooth is listed as an application. But see if it's listed there.
Next, factory restore the phone.
If it still doesn't you might just be out of luck. You could try the dealership, but they'd just have a salesperson try and no luck.
When I used to sell phones I'd have old people stop by all the time because the dealership wouldn't want to help them. Most of the times I could get it to work. Can try to see if someone at the phone dealer isn't busy and let them give it a try. Slide them a $10 or something if they can get it to work.