ACDelco 12653998 GM Original Equipment Engine Control Module Assembly This part requires programming and/or special setup procedures. GM Service Information or equivalent describes the procedures and special tools needed to ensure proper operation in the vehicle. Dictates the operation of your vehicles vital systems, which is critical to the performance of your vehicle GM-recommended replacement part for your GM vehicles original factory component Offering the quality, reliability, and durability of GM OE Manufactured to GM OE specification for fit, form, and function