Body Control System Circuit Description. Pontiac Firebird 2000

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2000 🢒 Firebird 🢒 Body and Accessories 🢒 Body Control System 🢒 Body Control System Circuit Description

Circuit Operation

This section is intended to provide the technician with an understanding of the body control module (BCM) operation. The BCM systems listed below are not described in detail in this section. For a detailed circuit description, refer to the following proceduresRefer to the following circuit descriptions for more detail:

•	Keyless Entry System Circuit Description

•	Content Theft Deterrent (CTD) Circuit Description

•	Vehicle Theft Deterrent (VTD)Circuit Description

•	Audible Warnings Circuit Description

•	Retained Accessory Power (RAP) Circuit Description

•	Power Door Locks Circuit Description

•	Rear Compartment Lid Release Circuit Description

•	Interior Lights Circuit Description

Wake-up and Sleep Modes

Wake-up signals are signals which turn on the BCM. Once active, the BCM begins monitoring and controlling the system functions listed above. With the ignition switch in the OFF position, the BCM ceases control of the system functions after a 10 minute period. This is the sleep mode. During the sleep mode the BCM monitors several circuits for changes in status. The BCM wakes up when a change is detected in any of the following inputs:

•	The courtesy lamps

•	The remote keyless entry system

•	The ignition switch

•	The park lamps

•	The headlamps

•	The side door locks

•	The rear compartment lid ajar indication switch

•	The ignition key lock cylinder

•	The theft deterrent shock sensor

Power Requirements

The BCM will operate properly with a system voltage of 9-16 volts.

Operating current measured at the BCM battery terminals in the awake mode should not exceed the following values:

•	75 milliamps with the ignition switch in the OFF position

•	250 milliamps with the ignition switch in the RUN position

Operating current measured at the BCM battery terminals in the sleep mode should not exceed the following values:

•	Two milliamps on vehicles without theft deterrent (UA6)

•	Three milliamps on vehicles with theft deterrent (UA6)

Operating current measured at the BCM IGN1 and IGN3 terminals should not exceed 15 milliamps.

Abbreviations

The following abbreviations are used throughout this section:

•	Body control module (BCM)

•	Data link connector (DLC)

•	Diagnostic trouble code (DTC)

•	Digital multimeter (DMM)

•	Powertrain control module (PCM)

•	Personal automotive security system (PASS-Key® II)

•	Retained accessory power (RAP)

•	Universal theft deterrent (UTD)

BCM Replacement

Technicians should not replace the BCM unless directed to do so by the diagnostic procedures in this section. Most system faults are traceable to faulty wiring, connectors or components. The BCM is very reliable and is not likely the cause of the fault. Do not replace the BCM before performing a complete diagnosis. This may result in the replacement of a good BCM and a recurrence of the fault.

Important:

•	If the BCM is replaced, refer to Body Control Module (BCM) Programming/RPO Configuration to program the new BCM to the current ignition key.

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A new BCM is shipped from the supplier in the factory test mode. This mode allows only limited functionality of the BCM controlled systems. When a new BCM is installed it is necessary to exit the factory test mode prior to returning the vehicle to the customer. To restore the BCM to normal operation, turn the ignition switch from the RUN position to the OFF position 10 times or enter the program mode as described in the theft deterrent system.