2018 S60 T5 Reduced Engine Performance
 

Hoping to get some help here. I had the car parked and running when the "Reduced Engine Performance" warning came up on the dash. I turned it off and it has not started since. I have replaced the main battery, teh spark plugs bought a new fuse for the positive terminal and checked the aux battery and it reads over 12.0 (It's about 4 years old). What else can it be? When I hit the start button it cranks and cranks but never starts. It then gives me a low battery warning (which is weird because one battery is new and the other has enough charge). I read about resetting the BMS and followed the steps and it still doesn't start. Other that the possibility of the starter being bad, any other advice on what to do here? The car has 67K miles, Thanks!

Start by having the car scanned for OBD fault codes.

Thanks! I've plugged my OBD scanner and it didn't generate any codes....