Description & Operation

WARNING: Deactivate air bag system before performing any service operation. See appropriate AIR BAG RESTRAINT SYSTEMS article. Do not apply electrical power to any component on steering column without first deactivating air bag system. Air bag may deploy.

The Body Control Module (BCM) controls the following functions: Remote Keyless Entry (RKE) system, Content Theft Deterrent (CTD) system, chimes, fasten seat belt indicator, Retained Accessory Power (RAP), power door locks, rear compartment lid release and interior lights.

Signals that activate BCM are known as "wake-up" signals. BCM is asleep when it is not controlling or monitoring the following wake-up functions: courtesy light system, remote keyless entry system, ignition switch, parking lights, headlights, door jamb switches, rear compartment lid ajar indicator switch, key-in-ignition switch and shock sensor inputs. When BCM is awake and wake-up signal is removed for 10 minutes, BCM will return to sleep. If BCM receives a door ajar wake-up signal and wake-up remains active after 10 minutes, BCM will turn off courtesy light (if illuminated) to prevent battery drain.

BCM battery terminals operating current should not exceed 75 milliamps while BCM is awake with ignition switch in OFF position. An approximate normal value with ignition switch in RUN position is 250 milliamps. If RAP is active, amperage may be higher. RAP allows operation of power door locks, convertible top and radio until 10 minutes have elapsed or a door is opened. When BCM is asleep, current should not exceed 2 milliamps (3 milliamps with theft deterrent system). BCM will go to sleep after ignition is turned off and 10 minutes has elapsed. BCM IGN 1 and IGN 3 terminals operating current should not exceed 15 milliamps. Most BCM functions will properly operate with a system voltage of 9-16 volts.