Service light on and code 189 and 171

Hello to all here at this forum. I have decided to join hoping I can get some help with my pool system. I have an odd shape poll with 15,000 gallons including the hot tub. A few days ago I noticed the service light on and numbers coming up on the display and a friend told me these were codes when something is wrong. I checked my manual and it said it could be the backboard but I just want to hear someone else tell me that's what it is. I still have chlorine in the pool but I don't know how long that will last. Can somebody advise me on what to do?
Thanks