Chosen Solution
Have an iPhone 8 Plus that has me confused. Over the past few days, the haptic feedback has been intermittent at best. No water exposure or drops recently to correlate unfortunately. The part that has me stumped is the haptics start working when the phone is warm-hot (like charging), but as soon as the phone drops back to ambient temp or colder (say chilled in a fridge for a few minutes), the haptics work less and less as the temp drops. At room temp it’s about 10% or less functional. Before popping it open, any thoughts/suggestions? I have a replacement Taptic Engine on order but only discovered the temperature correlation this evening. Edit: No other known functionality issues either. Audio, networking, TouchID, screen/touch seem good, battery health reports at 86%, phone is a warranty replacement (came with Apple warranty coverage, so presumably “Apple” Refurb’ed) phone that is roughly 1 year old.
Although you may not have dropped the phone in liquid, that’s not to say it was by the previous owner as you mentioned it was an apple refurbished device and in my personal experience, some “certified refurbished” devices, even from apple, shouldn’t have been refurbished.
