They have to be relearned... There is a tool that the dealer used on mine... I think I am getting ready to replace mine because the left front and left rear come on and off think the battery might be going bad or they got moisture in them...
Also I have heard you can put the truck in learn mode and let air out of each tire and the system will learn too....I have not tried tihs as of yet...
2015 GMC 2500 HD Denali Diesel..LML
Iridium Metallic Gray
CST 10" Lift Dual CST shocks
22" Fuel Forge Wheels 37" Toyo Open Country R/T
Lift Pump,5" Exhaust, Ladder Bars,Edge Insight2, Big Brake-Kit