Owners of 2017-2019 GMC Acadia vehicles may comment about the SES light on, or the engine may have a slight noise coming from the front of the engine’s belt area. The noise may or may not be present when it comes into the shop.
Upon investigation you may find DTC P0324 set in the ECM. You may hear a squeak noise at the belt area as well. GMC has determined that this DTC can be set by noise from the water pump. Listen to the water pump with chassis ears or a stethoscope for any unusual noise.
Watch the knock retard bank to bank on GDS2, then remove the belt and observe knock retard again. If there is a difference, replace the water pump and re-evaluate.