2002 Chevrolet Silverado 2500 HD - Engine And Powertrain Control Module

What is an Engine or Powertrain Control Module?

The engine control module (ECM), also known as the powertrain control module (PCM), is the main computer that controls your engine's performance functions and ensures your vehicle is operating its best. The PCM circuit board is coded with vehicle-specific software that acts as the brain of the engine, telling it how to run and operate properly. In newer vehicles, the engine control module contains software that controls nearly everything required to operate the engine, and sends alerts to notify you of any problems with the vehicle. The PCM has multiple functions and is responsible for regulating the four main operating systems in your vehicle - air-fuel ratio, ignition timing, idle speed, and variable valve timing. To regulate the functions across these systems and other vehicle areas, the control module monitors a wide range of sensors in different parts of the vehicle to make sure systems are operating correctly. When the ECM receives communication about a problem from one of these sensors, a trouble code is generated and triggers your vehicle's Check Engine light to illuminate or flash, depending on the error type. The engine control module receives and interprets information from these sensors almost instantly, and can alert you of a problem before you can detect any other noticeable symptoms. Over time, powertrain or engine control module can suffer damage that can limit their ability to communicate or process information appropriately. Because it regulates so many systems in your vehicle, a failing engine control module can present a multitude of symptoms. If you notice engine stalling, misfiring, or if your engine fails to start at all, it could be time to replace your ECM. O'Reilly Auto Parts carries replacement control modules for most vehicle types, in addition to the replacement engine management sensors you may need to keep it running its best. You can also enjoy free Check Engine light testing at your local store to help you begin your diagnosis and ensure you make the repair right the first time.