Diagnosis And Testing - Body Control Module

WARNING: This page is about a different car, the 2004 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The hard wired inputs to and outputs from the Body Control Module (BCM) may be diagnosed and tested using conventional diagnostic tools and procedures. Refer to the appropriate wiring information.

Conventional diagnostic methods may not prove conclusive in the diagnosis of the BCM. In order to obtain conclusive testing of the BCM, the Programmable Communications Interface (PCI) data bus network and all of the electronic modules that provide inputs to or receive outputs from the BCM must also be checked. The most reliable, efficient, and accurate means to diagnose the BCM, the PCI data bus network, and the electronic modules that provide inputs to or receive outputs from the BCM requires the use of a DRBIII(R) scan tool and the appropriate diagnostic information. The DRBIII(R) scan tool can provide confirmation that the PCI data bus network is functional, that all of the modules are sending and receiving the proper messages over the PCI data bus, and that the BCM is receiving the proper hard wired inputs and responding with the proper hard wired outputs needed to perform its many functions.

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIR-BAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.