This Preliminary Information communication provides information to the technician about vehicles that have a check engine light on. Technician may find Diagnostic Trouble Codes P1016 and / or P1017 set. Technician will need to follow publish Service Information diagnostics first. If Service Information diagnostics do not isolate a root cause of the concern General Motors Engineering is aware of this concern and is working on a correction. Dealer should communicate to the customer that we apologize for this inconvenience and that General Motors is working on a solution for this concern.