The CPC4 (Control Powertrain Controller) Module – What Trucks Use CPC4?

The CPC4 module is found in the Freightliner Cascadia and Western star trucks. It is approximately 7″ wide x 4.5″ deep by 1.5″ tall. It is often located under the dash or under the passenger seat, but its position can vary from truck to truck.

The Freightliner CPC4 is a computer that is responsible for monitoring and controlling many systems within these trucks. It acts like the brain of the truck, it receives information from various sensors that are located around the truck and also from switches and other electronic control units. It uses the information it collects to manage various processes that are happening within the vehicle. The sensors send a lot of information to the CPC4 including, the airflow in the engine and in the exhaust, the coolant temperature, how far the accelerator pedal is pushed down, the speed at that each wheel is turning and several other parameters. The Freightliner CPC makes many decisions every second, including how much fuel should be injected into each cylinder, when to fire the spark plugs and when the automatic transmission needs to be shifted to a different gear, in order to provide the best performance for the truck.

The CPC4 ensures that your truck gives a smooth and efficient performance, it makes decisions seamlessly when changes are necessary. Stored within it are sets of data for specific applications. These include: idle speed, maximum running speed and speed limitation. Programmable parameters are also stored within the CPC4.