timing chain tensioner failed while driving. replaced timing chain set. engine won't start and the above code was displayed. Anyone know what this means?
P15E8 - Engine shutdown time, plausibility: Time too short relative to temperature drop in engine coolant https://www.motoringalliance.com/library/all-about-mini-coopers-17/ecu-codes-chart---2nd-generation-mini-102/ Maybe it's a bad coolant temperature sensor or it may be unplugged.
Like Dave said it could be unplugged, check all your connections. Let us know what you find. Welcome to MA!