Might be the Water Pump
This bulletin applies to 2017-2019 GMC Canyon trucks equipped with a 3.6L engine. Some customers may comment that the SES lamp is on or the engine may have a slight noise coming from the front of the engine belt area. Upon investigation, you may find DTC P0324 set in the ECM.
GM has determined that at times the code can be set by noise from the water pump.
Listen to the water pump with a stethoscope or chassis ears to see if any unusual noise is heard. Watch the knock retard 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 the concern.