The old battery in my 2012 S60 T5 died and would not hold any charge in spite of many recharge attempts. However the car would always start with the old battery and a jump start with another battery. I went ahead and purchased a new replacement battery with the same specs but it would not crank or start. I searched this site and others and tried the following to no avail:
1. Jump starting the new battery with another didn’t work.
2. Pressing and holding the start button didn’t work in spite of numerous attempts.
3.Installing new a battery in both key fobs was not the solution either. Both fobs locked and unlocked the doors with the new battery installed.
4. There were no messages in the dash about an immobilizer.
5. I tried locking and unlocking the door 5 times in a row to reset but that didn’t work.
6. Turning the ignition on and off without cranking did not work.
7. The connections at the starter were firm and had no corrosion.
8. The engine was not locked up, I could turn it over manually.
What DID work was RESETTING the ODBC codes. After resetting it started right up with one touch and has not exhibited any problems!! Prior to changing the battery there were no DTC codes.
I hope will help someone save a trip to the dealership or countless hours trying so many things.