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Home >> Jeep >> 2005 >> Liberty Limited, 2.8 5, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Powertrain Diagnostic Procedures - Diesel >> System Description And Functional Operation >> Front Control Module
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Front Control Module

The KJ diesel is equipped with a Gateway module, which is referred to as the Front Control Module (FCM). The FCM transfers messages between the Controller Area Network (CAN) bus and the Programmable Communication Interface (PCI) bus. The FCM receives inputs from various sensors/modules and communicates those values to the ECM over the CAN bus network. The CAN bus network on the KJ is for inter-module communication only. The CAN Bus network consists of the following modules:

Diagnosis is done using the DRBIII®. The DRBIII® utilizes the SCI Transmit circuit to communicate with the ECM. The FCM and the ABS module utilize the PCI bus to communicate with the DRBIII®. Communication between these modules is essential for proper vehicle operation. The FCM and ECM will set DTCs if a fault occurs within the bus network. Refer to COMMUNICATION  for all the communication related DTCs.