2015 Buick Lacrosse "Service Airbag" light on

That code is for your seat sensor. Have you had the sensor checked to ensure it doesn't need to be replaced?
 
Thank you!

See if this helps. Certain airbag codes are PPM/OCC/OCSM codes that are tied in with the Airbag module.
1: All PPM/OCC/OPDS codes need to be diagnosed separately from standard air bag codes.
2: When a PPM/OCC/OPDS code is detected the Air Bag control module is working as designed
This code is a OCC/OCSM/OPDS code. Not a crash code.
When a vehicle is involved in an accident and airbags deploy, they store crash codes in the module and lock up the module. What we do here is to unlock the module clear all crash codes test the module for communication and recheck system for any crash codes or internal failure codes. If none are found we send the module back to the customer as repaired all crash codes erased.
To reset this code you will need to use a diagnostic scan tool that can communicate with the Airbag Control Module and make necessary changes if needed.
1. Navigate to SRS Airbag Menu
2. Look for a menu option called "Occupant " or "Recalibrate"
3. There you may see one option or two options. Clear codes and Zero out the weight
4. First zero out the weight sensor (occupant seat sensor). Then press clear codes
5. If the passenger seat has been replaced and the sensors in the seat were not transferred from the original seat to the seat that is now in the vehicle can also cause airbag issues.
If none of this was helpful and you still are having issues. Feel free to email me if you need further assistance.

It was working fine before I disconnected and reinstalled the seat.