iPhone 15 battery, logic board, and Taptic Engine replacement under warranty

For practical purposes, in lieu of repairing and returning your own iPhone, Apple will often exchange an iPhone for a renewed/refurbished iPhone of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. If repaired and returned, the entire logic board and battery will be replaced.

Unless you have benefit of an active AppleCare plan, an out-of-warranty repair while expensive will be somewhat less than the cost of a replacement iPhone. As for out-of-warranty repair costs, Apple offers a fixed-price price repair. You can verify eligibility and cost for your region/country here:

iPhone Repair & Service - Apple Support

If you have an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.

Apple will rarely exchange an item that requires repair unless the failure occurs when new, or shortly thereafter - Apple's warranty terms stipulating that a device may be exchanged for a renewed/refurbished item. As your iPhone is outside of its initial one-year limited warranty, it is very unlikely that an exchange for a brand-new device would be entertained at all.

If an unauthorized service provider has replaced the battery of your 14-month-old iPhone and carried out the repair incorrectly, or worse, swapped out some original components without your knowledge, this type of issue could arise. In your case, Apple has determined that the repair requires replacing the battery, the logic board, and the Taptic Engine. This type of repair is classified as a mid-system repair, which involves replacing nearly all of the phone’s internal components, leaving only the display and the rear casing intact. The specific fault identified in your device is linked to the logic board, which is the central hub responsible for managing the phone’s operations.

Vanchanzo wrote:

where battery was unverified and phone would not charge -

Parts and service history

With iPhone 12 models and later using iOS 15.2 and later, you can go to Settings > General > About to see the parts and service history of your iPhone and you can see if the camera has been replaced. If the repair was done using genuine Apple parts and processes, you will see "Genuine Apple Part" next to Camera.

• You will see an Unknown Part  message if the camera installation is incomplete or if the camera:
• Was replaced with a nongenuine camera
• Was already used or installed in another iPhone
• Isn't functioning as expected

This message doesn't affect your ability to use your iPhone or access your camera.

Learn more about iPhone parts and service history.

Parts and service history

With iOS 15.2 and later and iPhone XR, iPhone XS models, and later—including iPhone SE (2nd and 3rd generation)—you can go to Settings > General > About for the parts and service history of your iPhone. You can also find out if the battery has been replaced. If the replacement was done using genuine Apple parts and processes, "Genuine Apple Part" will appear next to Battery.