Diesel Models
POWERTRAIN CONTROL MODULEThe center of the electronic control (EC) system is the powertrain control module (PCM). The PCM contains both engine and transmission microprocessors. Operating information, as well as fault information, is communicated between the two processors via controller area network (CAN) communications. Both can be programmed individually, however replacement of the PCM is as an assembly. The PCM has three electrical connectors (122 pins total). The PCM receives input from sensors and other electronic components (switches, relays, etc.) and places this information into random access memory (RAM) or keep alive RAM. Based on information programmed into its read-only memory (ROM), the PCM generates output signals to control various relays, solenoids and actuators. For vehicles equipped with manual transmissions, only two electrical connectors are used.
The TCM controls the power monitor strategy. The power monitor monitors engine speed at idle. If an abnormal engine speed increase is detected, the power monitor will command the fuel injection control module (FICM) off in an effort to maintain a normal idle speed. For manual transmission vehicles, the power monitor is the only active TCM function. DTCs will be stored if the power monitor is active.