iPhone 4S Bluetooth Doesn't discover any devices

Hi,

I've iPhone 4S in which Bluetooth doesn't work from iOS 8.4. Till 8.3 it was working fine. I've tried "Reset Network Settings", "Reset All Settings", "Reboot Phone", "Restore Option", "Restore in DFU mode" and none of the option doesn't help. After which I contacted Apple Support and the also suggested me the options which I have tried earlier. I've installed the debugging profile for Bluetooth and saw the BTStack was crashing frequently. I went to Apple Service, they changed the antenna to see if that fixes the problem but it didn't.

Upgrading iOS to 8.4.1 and now to 9 doesn't solve the issue.

These are the devices which were working till I had iOS 8.3 on my phone and none of them work now,

* Creative WP-450 Headset

* 42LG LE5500 Television

* Ford Figo In-Built Audio System

After very long time, sometimes phone discovers the device but when I try to pair, it gives, "Make sure the device is in pair mode" after some 30 secs.

Any ideas on how to fix this?

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Bharathiraja