For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition
65 WarningEngine Control Module Description Engine Control Engine Control Module
The Engine Control Module (ECM) interacts with many emission related components andsystems, and monitors emission related components and systems for deterioration. OBDII diagnostics monitor the system performance and a diagnostic trouble code (DTC)sets if the system performance degrades. The ECM is ...