This vehicle is equipped with a Body Control Module (BCM). The BCM performs multiple body and engine control functions. The following vehicle systems are directly connected to the BCM:

This vehicle also has the following systems:

These vehicle systems communicate with each other on an interconnecting bus, known as the Class 2 serial data link.

Some electrical components are directly connected and controlled by their system module. Other systems accomplish this feature by sharing data information with other systems on the Class 2 serial data link in order to execute various vehicle functions. All of the system data information (sensors, switches, etc.) may be monitored by any system module that completes the computer system.

All systems on the Class 2 serial data link use a communication process similar to a telephone system. Large amounts of information may be exchanged on a single data wire.

Communications between each system is accomplished by sending a digitally coded message. The digitally coded message consists of specific information a system module must follow. Each system module is assigned a recognition code (address). When a message is sent out on the Class 2 serial data link, the BCM provides more accurate and reliable computer system control functions. The BCM uses information from other systems in order to execute some functions. Before further diagnosis, review the following general information:

Review this information in order to gain the following benefits:

The Body Control Module (BCM) is capable of accomplishing multiple body control functions Components directly connected to the BCM are controlled by the BCM's outputs. The BCM controls the outputs based on the following information:

The BCM evaluates this information and controls the certain body systems by commanding an output on or off.

The BCM is also capable of commanding other vehicle systems to control functions that are not directly wired and/or controlled by the BCM. The BCM accomplishes this task by sending specific messages on the Class 2 serial data link. The vehicle system capable of performing such function will respond to the BCM message.

The BCM performs the following functions:

Retained Accessory Power (RAP)

The Retained Accessory Power (RAP) feature allows the operation of the following functions for 10 minutes (or until a vehicle door opens) after the ignition switch has been turned from the RUN or ACC to the LOCK or OFF position:

Refer to Retained Accessory Power (RAP) Circuit Description in Retained Accessory Power (RAP) for more information.

Audible Warnings

The Audible Warnings system performs the following functions:

Refer to Audible Warnings Circuit Description in Instrument Panel, Gauges and Console for more information.

Interior Lighting

Interior Lighting system performs the following functions:

Refer to Interior Lights Circuit Description in Lighting Systems for more information.

Backup Lights

Automatic Door Locks

The Automatic Door Locks system performs the following functions:

The BCM provides feature customization of these door lock functions:

Refer to Power Door Locks Circuit Description in Doors for more information.

Keyless Entry

The Keyless Entry system performs the following functions:

Refer to Keyless Entry System Circuit Description in Keyless Entry for more information.

PASS-Key® II Theft Deterrent

The Personal Automotive Security System (PASS-Key® II) is a vehicle theft deterrent system. The PASS-Key® II is designed in order to prevent vehicle theft by disabling the engine from starting unless an ignition key with a specific resistor pellet code is used in the ignition lock cylinder.

The ignition lock cylinder contains the resistor sensing contacts. These contacts touch the resistor pellet embedded in the ignition key. When the ignition key is inserted in the ignition lock cylinder, the resistor pellet completes the key detection circuit (CKT 1073 and CKT 1074).

When the ignition switch is turned from the OFF to the RUN position, the BCM applies a 5 V reference voltage to CKT 1073. The BCM reads the resistor pellet code and compares the stored resistor pellet code against the ignition key resistor pellet code for a correct match.

Upon detecting a correct match, the BCM sends a fuel enable password to the PCM through the Class 2 serial data link. As a result, the PCM enables the theft deterrent relay. This action allows fuel delivery to the engine.

If the key resistor pellet is incorrect, the PCM performs the following actions:

This vehicle disable period state lasts approximately 3 minutes. The SECURITY indicator flashes when the ignition switch is turned to the RUN position. Disconnecting the battery will not clear the timer sequence. The timer sequence resumes when the battery power is restored. If a proper key is inserted during the vehicle disable period, the vehicle will not start until the 3 minute time period elapses. After the 3 minute time period, the SECURITY indicator changes from a flashing state to a solid ON state. At this time, the BCM enters the theft deterrent re-learn mode. The engine will start if the correct ignition key resistor pellet is used.

Refer to Content Theft Deterrent (CTD) Circuit Description in Theft Deterrent for more information.

The BCM performs these functions in the wake-up state. The BCM enters the sleep state when the following conditions exist:

The BCM must detect certain wake-up inputs before the BCM enters the wake-up state. The BCM monitors the inputs during the sleep state. This condition allows the BCM to switch between the awake state and the sleep state.

The BCM enters the wake-up state when receiving activity on any of the following inputs:

The sleep state occurs when the following conditions exist:

When the BCM detects a wake-up condition, the BCM enters the wake-up state. The conditions listed above are called Wake-Up Inputs. These wake-up inputs cause the BCM to change from a sleep state to a wake-up state. The BCM then begins active control and monitoring. The BCM has the ability to monitor for these wake-up inputs in the sleep state.

The BCM enters the sleep state when all of the following conditions exist:

The BCM has 3 main voltage feeds and 1 ground. CKT 2340 is used in order to provide power for the BCM's logic and internal driver operation. CKT 1540 provides power for the automatic door lock. CKT 240 provides power to the courtesy lights.

The following components provide direct input to the BCM. Other systems may use this input information in order to perform certain functions. Refer to Body Control System Schematics for BCM connector and terminal locations.

The BCM directly controls the following outputs. Other systems may request the BCM to control these outputs for certain functions. Refer to Body Control System Schematics for BCM connector and terminal locations.