The Body Control Module (BCM) performs the following functions:

A/C Compressor Control

The Powertrain Control Module (PCM) and the Body Control Module (BCM) share the hardware and the software for control of the A/C compressor clutch. The PCM and the BCM communicate this information over the Class 2 serial data line.

The control compressor clutch function looks at the other BCM compressor functions and determines if any of these functions are disabling the engagement of the compressor clutch.

The BCM performs the following software functions:

The PCM performs the following functions:

The drive compressor clutch function looks at the BCM request and at the other PCM compressor functions. This determines whether or not the compressor clutch should be engaged.

Audible Warnings

The Body Control Module (BCM) determines the priority of the chime requests and the highest priority chime request is activated. The functions which cause the audible warning to be activated by the BCM are listed from lowest to highest priority:

1. Automatic Door Lock (ADL)-delayed locking verification
2. Automatic Door Lock (ADL)-programming option notification
3. Check gauges
4. Headlamps left on
5. Key left in the ignition
6. Oil life reset
7. Overspeed warning (export only)
8. Park brake
9. Tire Inflation Monitoring System (TIMS) reset
10. Turn signal left ON
11. Seatbelt not fastened

Only 1 alarm may be ON at a given time. For simultaneous chime conditions, the chimes have the priority level as listed. For simultaneous chime conditions, complete all of the pending low priority alarms after completing the higher priority alarms. If alarms occur concurrently, complete the highest priority repetition rate exponential decay to 2% of peak value before transitioning to the next alarm repetition rate.

Following an ignition transition, the check-gauges chime shall queue while waiting for the seatbelt chime to finish. After the seatbelt chime stops, the queued check-gauges chime shall sound for as long as the condition still exists.

The repetition rate for each function is as follows:

Function	Repetition Rate
Seatbelt	50/min
Key In Ignition	(Note 1)
Headlamps	300/min
Turn Signal	(Note 2)
Park Brake	300/min
Check Gauges	50/min (3 chimes total)
Overspeed	150/min
TIMS	50/min (8 chimes total)
Oil Life	50/min (8 chimes total)
Automatic Door Lock (ADL) Delayed Lock	180/min (3 chimes total)
Automatic Door Lock (ADL) Prog. Option	(Note 3)
Note 1: The key-in repetition rate is 150/min for 3 seconds minimum, then 18/min at a 50/min decay rate. Note 2: The turn signal chime repetition rate is synchronized with the turn signal flash rate. The chime is synchronized with the leading edge of the turn signal, but decays at a fixed, nominal rate (as the turn signal rate changes). Note 3: The Automatic Door Lock (ADL) programming option notification chime is at a 1 Hz repetition rate. The number of chimes depends on the number called out by the Automatic Door Lock (ADL) programming option chosen.

Audio Chime Function	Ignition Key Off/lock	Ignition Key Accy	Ignition Key Run/Start
Automatic Door Lock (ADL) Delayed Lock	Yes	Yes	Yes
Automatic Door Lock (ADL) Programming Option	No	No	Yes
Check Gauges	No	No	Yes
Headlamps On	Yes	Yes	No
Key in Ignition	Yes	Yes	No
Oil Life Reset Acknowledge	No	No	Yes
Overspeed (Export)	No	No	Yes
Park Brake	No	No	Yes
Seatbelt Not Fastened	No	No	Yes
TIMS Reset Acknowledge	No	No	Yes
Turn Signal On	No	No	Yes
Yes=function enabled, No=function disabled

Upon a loss of Powertrain Control Module (PCM) Class 2 serial data, the chime turns OFF for the following conditions associated with the PCM indicator messages:

Upon a loss of Electronic Brake Control Module (EBCM) Class 2 serial data, the chime turns OFF for the following conditions associated with the EBCM indicator messages:

Upon a loss of instrument cluster Class 2 serial data, the chime turns OFF for all check-gauges chimes associated with the instrument cluster indicator messages.

Upon a loss of Body Control Module (BCM) Class 2 serial data, the chimes turn OFF for all check-gauges chimes associated with the BCM indicator messages.

Regardless of Class 2 serial data condition, the following chimes become active when the necessary conditions are present:

Refer to Diagnostic System Check - Audible Warnings .

Check Gauges

The check-gauges alarm sounds 3 tones, at a rate of 50 tones per minute, once per ignition cycle (once per each indicator transition to active) when any of the following indicators become active, the engine is running, and more than 5 seconds have elapsed since the engine began running:

Headlamp On Warning System Description and Overview

The headlamps ON alarm sounds at a rate of 300 tones per minute when the following conditions are true:

The alarm deactivates when any one of the above conditions changes.

Key In Ignition

The key-in-ignition alarm sounds at a rate of 150 tones per minute for 3  seconds , then switch to 18 tones per minute when the following conditions are true:

The alarm deactivates when any one of the above conditions changes.

Oil Life Reset

The oil life reset acknowledgment alarm sounds 5 tones, at a rate of 50 tones per minute when the cluster transmits an Engine Oil Fluid Remaining Life Command=100% to the Powertrain Control Module (PCM).

Overspeed Warning (export only)

The overspeed warning function is disabled until it is enabled via a Class 2 serial data message. The alarm sounds at a rate of 150 tones per minute when the vehicle speed exceeds 120 km/h (75 mph). The overspeed chime stops when the vehicle speed drops below 110 km/h (69 mph) for greater than 1 second.

Park Brake Warning

The Park Brake alarm sounds at a rate of 300 tones per minute when the following conditions are true:

The alarm deactivates when any one of the above conditions changes.

Seatbelt Not Fastened

The seatbelt-not-fastened alarm sounds at a rate of 50 tones per minute when the following conditions are true:

The alarm deactivates when any one of the above conditions changes.

Tire Inflation Reset

The tire inflation reset acknowledgment alarm sounds 5 tones, at a rate of 50 tones per minute when the low tire pressure reset report is sent out by the Electronic Brake Control Module (EBCM).

Turn Signal (Oldsmobile only)

The turn signal ON alarm activates when ignition is active and the turn signal has been active for greater than 1.2 km (0.75 mi). The alarm synchronizes with the turn signal flash rate. The chime synchronizes with the leading edge of the turn signal and the chime decays at a fixed nominal rate as the turn signal changes.

Automatic Door Lock (ADL) Delayed Lock

This function locks and unlocks the vehicle doors through a variety of different features.

Manual door locking and unlocking alternates with the automatic door locking/unlocking providing 3 or 4 different modes of operation. Automatic locking occurs when the vehicle is shifted out of park (automatic transmission), or after the first key-on when the vehicle speed exceeds a given value (manual transmission). Automatic unlocking occurs when the ignition switch moves from the RUN to the OFF position. The modes of operation are programmable by the driver and are defined as follows:

Mode Selected	Shift out of Park or Vehicle Speed	Ignition RUN to OFF
1=All Lock/ All Door Unlock	All Doors Lock	All Doors Unlock
2=All Lock/ Driver Unlock Only. This mode is only available with Remote Control Doorlock Receiver equipped vehicles.	All Doors Lock	Only Driver's Door Unlocks
3=All Lock/ No Unlocking	All Doors Lock	No Unlocking
4=No Locking/ No Unlocking	No Locking	No Unlocking

The remote control doorlock receiver locking/unlocking is controlled by pushing the buttons on the Remote Control Doorlock Transmitter. This feature also flashes the parklamps and chirps the horn as feedback when the doors are actually locked.

If the vehicle is stopped, but not in PARK, the relocking feature relocks the vehicle doors after you manually unlock a door, open the door, and close the door. When the vehicle speed exceeds 3 km/h (5 mph), the vehicle doors are relocked.

The delayed locking feature allows a delayed lock of the vehicle after the driver leaves. This feature is started by pressing a lock switch with a door open and the key out of the ignition switch (a chime occurs as feedback). When all the doors are closed, the doors are locked after 7 seconds. If a door is opened during the 7-second delay, the delay time-out is reset after the door is closed. This allows the driver to start the feature, close the front door, open the back door (in order to remove a briefcase, for example), and close the back door. All of the doors automatically lock after 7 seconds.

You can override the delayed lock by pressing the door lock switch a second time. This feature also flashes the parklamps and chirps the horn as feedback when the doors are actually locked.

The anti-lockout feature prevents the driver from locking the keys in the car. If the keys are in the ignition switch and a door is open, pressing a door lock switch does not lock the doors. However, there are 3 ways to override this:

Battery Rundown Protection

Battery Rundown Protection helps prevent the battery from deep discharge when you have inadvertently left the interior/courtesy lighting ON (glove box door open, door ajar, map light on, panel dimmer on, etc.). Battery Rundown Protection performs this function by turning off the inadvertent power output. This provides a high side drive for the interior/courtesy lighting.

Once the ignition switch is turned OFF, a time-out period begins. When the time-out expires, the inadvertent output is turned off. The length of time before the timer expires depends on the accumulative vehicle mileage. If the mileage is under 24 km (15 mi), the vehicle is assumed to be in the plant or the dealership lot, and the time out period of 3 minutes is used. If the accumulative mileage is greater than 24 km (15 mi), the vehicle is assumed to be in the hands of the customer, and time out period of 20 minutes is used.

While the inadvertent power output is OFF, the inadvertent feed back is monitored. If a high to low transition occurs, or if a hardware/software wake up occurs, the inadvertent output is turned back ON and the timer is restarted.

Cruise Cancel (Oldsmobile only)

The Cruise Cancel Switch operates in the following manner. The Body Control Module (BCM) reads the cruise control cancel switch and determines when the switch is pressed. The BCM transmits a Class 2 serial data message to the Powertrain Control Module (PCM) to disable the cruise.

The brake switches operate in the following manner. The Electronic Brake Control Module (EBCM) reads the brake fluid level switch. When the switch closes due to low brake fluid, the EBCM transmits a Class 2 serial data message to the PCM indicating the status of the brake fluid switch.

The park brake switch is read by the BCM. When the park brake is activated, the BCM transmits a Class 2 serial data message to the PCM indicating the status of the park brake switch. The PCM takes both brake messages and forces the inhibit circuit to disable the cruise. In the event of a loss of Class 2 serial data, the PCM forces the inhibit circuit to the high state disabling the cruise.

Class 2 Data Line

Class 2 data is a high speed serial data transmission. The Class 2 data line includes the following control modules:

Driver Warning System

The Body Control Module (BCM) is responsible for interpreting most of the driver warnings. The remaining driver warning information is sent on to the instrument cluster in the form of a Class 2 serial data bus message. The BCM sends the following messages to the instrument cluster :

ABS Indicator

The amber ABS indicator illuminates when the Electronic Brake Control Module (EBCM) transmits a Class 2 serial data message to the instrument cluster indicating an ABS malfunction. The instrument cluster commands the ABS indicator ON. In the event of a Class 2 serial data loss, the ABS indicator illuminates.

Brake Indicator

The red BRAKE indicator illuminates when Ignition 1 is active and the park brake is engaged. The Body Control Module (BCM) transmits a Class 2 serial data message to the instrument cluster indicating the park brake status. Also, the BRAKE indicator illuminates when the Electronic Brake Control Module (EBCM) detects a brake fail condition. The instrument cluster commands the BRAKE indicator ON. The BRAKE Indicator turns OFF under the following conditions:

If the EBCM commands the BRAKE indicator to illuminate, the cruise function is canceled. In the event of an EBCM Class 2 serial data loss, the BRAKE indicator illuminates . In the event of a BCM Class 2 serial data loss, the park brake status and the indicator remain in their last states.

Check Tire Pressure (Pontiac) / Low Tire Pressure (Oldsmobile)

The amber CHECK TIRE PRESSURE (Pontiac) or the LOW TIRE PRESSURE (Oldsmobile) indicator is commanded ON by the Electronic Brake Control Module (EBCM) via a Class 2 serial data message to the instrument cluster.

To reset the tire pressure, the Body Control Module (BCM) reads a momentary switch found in the LH I/P Wiring Harness Junction Block and transmits a Class 2 serial data message to the instrument cluster. The switch must be momentarily depressed twice (2) in order to enter the Tire Inflation Monitoring System (TIMS) reset stage. At this point the CHECK TIRE PRESSURE (Pontiac) LOW TIRE PRESSURE (Oldsmobile) flashes at 1 Hz by the instrument cluster to inform the driver that the TIMS reset has chosen Oil Life or (TIMS). The driver then has a time period to depress and hold the switch. Once this condition is met the instrument cluster sends out a Class 2 serial data Low Tire Pressure Reset message. The EBCM reacts to this message by determining the new tire pressure. In addition, the indicator illuminates for a period of time and then turns OFF when the reset period is complete. The reset program is exited under either of the following conditions:

When the BCM receives the reset acknowledge report from the EBCM, an acknowledgment chime shall sound.

Upon a loss of Class 2 serial data between the EBCM and the instrument cluster, the commanded indicator remains in its last state. Upon a loss of Class 2 serial data between the BCM and the instrument cluster, the BCM commanded chime state remains OFF.

Change Oil/Oil Life Indicator

The Powertrain Control Module (PCM) perform a powertrain specified oil life program and transmits a Class 2 Oil Life serial data message to the instrument cluster indicating the percent of oil life remaining. The instrument cluster compares the percent oil life remaining to a calibrated threshold and dictates the CHANGE OIL/OIL LIFE indicator state.

To reset the Oil Life indicator, the Body Control Module (BCM) reads a momentary reset switch input and transmits a Class 2 serial data message to the instrument cluster indicating that the switch has been closed. The switch must be momentarily depressed, for 3 seconds, in order to enter the Oil Life reset stage. At this point the instrument cluster flashes the CHANGE OIL/OIL LIFE indicator at 1 Hz in order to inform the driver that this program is the one chosen to be reset. (You can also reset Oil Life or Tire Inflation Monitoring System from this switch). The driver then has 3 seconds to depress and hold the switch. The instrument cluster sends out a Class 2 Oil Life serial data command message. The Powertrain Control Module (PCM) reacts to this message by resetting the remaining Oil Life to 100%. In addition, the CHANGE OIL / OIL LIFE indicator goes ON solid for a period of time and then turns OFF when the reset period is complete. The reset program is exited if either one of the following conditions is true:

When the BCM receives the command from the instrument cluster, an acknowledgment chime shall sound.

In the event of a PCM Class 2 serial data failure, the instrument cluster commanded indicator shall remain in its last state. In the event of a BCM Class 2 serial data failure, the chime shall not be triggered.

Check Oil Indicator (V6 only)

The amber check oil indicator illuminates when the Powertrain Control Module (PCM) reads the Oil Level Switch and transmits a Class 2 message to instrument cluster indicating a low oil level condition. If the low oil Level option is false, all Class 2 activity on the instrument cluster stops. The instrument cluster will not send out any request for the low oil level condition command and will not issue a low oil level condition report. If a loss of PCM Class 2 serial data occurs, the check oil indicator will not illuminate unless the indicator was illuminated when the event occurred.

Cruise Indicator

The green CRUISE indicator illuminates when the Powertrain Control Module (PCM) transmits a Class 2 message to the instrument cluster indicating that Cruise Control is engaged. The instrument cluster commands the CRUISE indicator ON. If the Electronic Brake Control Module (EBCM) commands the BRAKE indicator to illuminate, the Cruise function is canceled. If a Class 2 serial data loss occurs, the CRUISE indicator will not be illuminated unless the indicator was illuminated prior to the event.

High Temperature Indicator

The high temperature Indicator function handles the control of the Engine Temperature Gauge Display and the red High Temperature indicator. The Powertrain Control Module (PCM) reads the Coolant Temperature Sensor, filters the messages, and sends the coolant temperature to the instrument cluster via a Class 2 serial data message. The PCM monitors the coolant sensor in order to determine a fault. The PCM transmits the Class 2 serial data coolant temperature report messages to the instrument cluster for the temperature gauge display and for the high temperature indicator control.

The instrument cluster receives the engine temperature data in the Class 2 serial data message from the PCM. The instrument cluster converts this data into a temperature gauge pointer position which drives the gauge pointer. The instrument cluster also uses this data in order to determine the high temperature indicator control.

The Body Control Module (BCM) looks for the high temperature indicator Class 2 serial data report from the instrument cluster and triggers a chime when the indicator is ON.

High Beam Indicator

The blue high beam indicator is a distributed function between the Body Control Module (BCM) and the instrument cluster. The BCM reads the high beam bulb voltage, and divides by the system voltage in order to determine a percent value. This value is compared against a calibration in order to determine if the high beams are ON. The BCM then transmits the status of the high beams to the instrument cluster via the Class 2 serial data bus. The instrument cluster then commands the high beam indicator accordingly. In the event of a Class 2 data link failure, the high beam indicator will not illuminate unless the indicator was illuminated prior to the Class 2 data link failure.

Low Engine Coolant Indicator

The red low coolant indicator illuminates in order to indicate to the driver that the engine coolant level is low. The engine coolant level switch is a discrete input to the Body Control Module (BCM) which closes when the engine coolant is low. The indicator illuminates when the input has been active low for at least 10 seconds and the ignition switch is in the RUN position. The indicator is commanded OFF if the switch input goes inactive for at least 2 seconds. This is a distributed function between the BCM and the instrument cluster. The BCM reads the status of the engine coolant level switch input in order to determine the indicator control. Then the BCM sends the control state to the instrument cluster via the Class 2 serial data bus. The instrument cluster reads the low coolant indicator control state in the Class 2 serial data message and controls the indicator directly. If a Class 2 data link fails, the low coolant indicator illuminates.

Low Fuel Indicator

The amber low fuel indicator turns ON in order to indicate to the driver that the fuel level has dropped to a calibrated point below 1/16 of a tank. The indicator is turned OFF when the fuel level rises back above ¼ of a tank. The fuel level is determined from the fuel level sense and display function and is then used by the low fuel indicator. This is a distributed function between the Powertrain Control Module (PCM) and the instrument cluster. The instrument cluster reads the low fuel indicator control state in the Class 2 message and controls the indicator directly. If a Class 2 data link fails, the low fuel indicator does not illuminate unless the indicator was illuminated prior to the Class 2 data link failure.

Low Wash Indicator

The amber LOW WASH indicator turns ON in order to indicate to the driver that the washer fluid level is low. The low washer fluid level switch is a discrete input to the Body Control Module (BCM) which closes when the washer fluid level is low. The BCM commands the instrument cluster to illuminate the indicator when the input has been active for a calibratable time (at least 30 seconds). The BCM commands the instrument cluster to turn the indicator OFF, if the switch input goes inactive for a calibratable time (at least 30 seconds). If a Class 2 data link fails, the LOW WASH indicator does not illuminate unless the indicator was illuminated prior to the Class 2 data link failure.

Oil Pressure Indicator

The red oil pressure indicator turns ON when the Powertrain Control Module (PCM) transmits a Class 2 message to the instrument cluster indicating a low oil pressure condition. The instrument cluster commands the oil pressure indicator ON over the Class 2 serial data interface. If a loss of Class 2 serial data occurs, the oil pressure indicator does not illuminate unless the indicator was illuminated when the event occurred. If a Class 2 data link fails, the oil pressure indicator does not illuminate unless the indicator was illuminated prior to the Class 2 data link failure.

PRNDL

The Powertrain Control Module (PCM) reads the transaxle range switch and transmits the selected gear position over the Class 2 serial data link to the instrument cluster.

Seat Belt Indicator

The seat belt switch (not for Oldsmobile Export) is a discrete input to the Body Control Module (BCM) which opens when you insert the seat belt into the buckle. The BCM commands the instrument cluster to illuminate the red seat belt indicator under either of the following conditions:

Upon either transition, the seat belt indicator glows steady for 20 seconds and then flashes at 1 Hz for 55 seconds. The indicator turns OFF when any one of the following conditions becomes true:

If a Class 2 data link fails, the seat belt indicator does not illuminate unless the indicator was illuminated prior to the Class 2 data link failure.

SERVICE VEHICLE SOON Indicator

The amber SERVICE VEHICLE SOON indicator is an alert to the driver whenever there are specific current codes stored in the Body Control Module (BCM) or in the event of a loss of Class 2 serial data. The SERVICE VEHICLE SOON indicator also remains illuminated until the BCM has been reprogrammed.

Security Indicator

The red SECURITY lamp whether the Passlock® data was incorrect. The Body Control Module (BCM) sends to the instrument cluster via the Class 2 serial data bus the message to turn ON or OFF the SECURITY indicator. The SECURITY indicator turns ON under either of the following conditions:

The SECURITY indicator flashes when the BCM detects a tamper or the PCM fuel disable time-out bit is set in the last vehicle security status message received since the ignition switch was turned to the RUN position.

For more information on the vehicle theft deterrent system, refer to Theft Deterrent System.

Engine Cooling Fan Control

The engine cooling fan control is partitioned between the Powertrain Control Module (PCM) and the Body Control Module (BCM) via Class 2 serial data bus. The main control resides in the BCM. The BCM sends a fan speed command to the PCM which processes this command along with its own fan request in order to determine the actual fan speed. If a loss of Class 2 serial data occurs, the PCM assumes control of the engine cooling fan.

For more information on the engine cooling fan controls, refer to Engine Controls.

Enhanced Traction Control-TRAC OFF Indicator

The Electronic Brake Control Module (EBCM) receives a Class 2 serial data message from the Body Control Module (BCM) indicating a traction switch activation. The EBCM determines the state of the TRAC OFF indicator and sends a Class 2 serial data message to the instrument cluster commanding the indicator state. The traction control switch is a momentary switch input into the BCM, which detects the switch activation and sends the Class 2 serial data message. If an EBCM Class 2 failure occurs, the TRAC OFF indicator will not illuminate unless the indicator was illuminated prior to the Class 2 failure.

Exterior Lighting Control

The Body Control Module (BCM) controls exterior lighting which includes the following:

Daytime Running Lights (DRL) operate the high beam headlamps at a reduced intensity under the following conditions:

The DRL activates if the transmission is not in to PARK and the park brake is OFF. The DRL remains ON and latch ON if the park brake is ON and the vehicle speed is above the threshold. The vehicle is defined to be in motion if the transmission is not in PARK and the park brake is not set.

Automatic lighting control turns on the parklamps and the headlamps when the ambient light sensor detects a low ambient light level. The system assures that the headlamps/parklamps are ON if the driver is operating the vehicle after dark.

If the ignition switch is turned to the RUN position in a low ambient light level area, the automatic lighting control becomes active immediately, otherwise 8 seconds must elapse before the automatic lighting control is activated. If the park brake is set when the ignition switch is turned to the RUN position, the automatic lighting control is disabled until the park brake is released. If the automatic lighting control is active and a high ambient light level is detected, 20 seconds must elapse before the automatic lighting control is turned OFF. The headlamps are disabled during engine crank.

The front foglamp relay activates when all of the following conditions occur:

The front foglamp switch is a momentary contact switch for the Oldsmobile and a latching switch for the Pontiac.

The rear foglamp activates when all of the following conditions occur:

The rear foglamp switch is also a momentary switch.

Foglamp relays are always OFF whenever a short to battery fault is detected on the foglamp relay output driver.

The backup lamps are the only exterior lamps that are not controlled by the Body Control Module (BCM).

Gauge Control

The Body Control Module (BCM) receives Class 2 serial data messages from the Powertrain Control Module (PCM) to determine the following gauge information:

Engine Coolant Temperature

The Body Control Module (BCM) handles the control of engine temperature gauge display and the High Temperature indicator.

The Powertrain Control Module (PCM) reads the engine coolant temperature sensor, filters the data, and sends the engine coolant temperature to the instrument cluster via a Class 2 serial data message. The PCM monitors the engine coolant sensor and determines whether the has malfunctioned. The PCM transmits the Class 2 serial data coolant temperature report messages to the instrument cluster in order to determine the temperature gauge display and to the high temperature indicator control.

The instrument cluster receives the engine temperature data in the Class 2 serial data message from the PCM and converts this message into a temperature gauge pointer position which drives the gauge pointer. The instrument cluster also uses this message in order to determine the high temperature indicator control.

The BCM looks for the high temperature indicator Class 2 serial data report from the instrument cluster and triggers a chime when the indicator is ON.

Fuel Level Sensing

The Powertrain Control Module (PCM) reads the fuel level sensor, filters the data, and then sends a fuel level Class 2 serial data message to the instrument cluster for display. The instrument cluster drives the fuel gauge pointer. The PCM is responsible for sending a fuel related Class 2 serial data message so that fuel level sensing is started when Ignition 0 is ON, however the fuel level is not displayed until Ignition 1 is ON. This is done in order to reduce the latency of the fuel gauge display during key-on.

The Body Control Module (BCM) looks for the low fuel indicator Class 2 serial data report from the instrument cluster and triggers a chime when the indicator is ON.

Generator Idle Boost (LD9 Only)

The generator idle boost function (4 cylinder applications) provides a boost of engine RPM when multiple loads on the electrical system are present during engine idle. This is done to minimize the battery discharge and is accomplished by raising the engine idle RPM. Thus higher generator output is produced when the vehicle is idling. This function's operation can be calibrated OFF if needed.

Interior Lighting Control

The interior light control function provides convenience and security by turning on the interior courtesy lights under several conditions. The following conditions enable the courtesy lamps:

When the driver leaves the vehicle (the ignition switch is turned OFF for more than 2 minutes), the interior lights are first step dimmed, and then theater dimmed to the OFF state.

Panic Alarm

The panic alarm is an alarm system that you can trigger by pressing the panic button on the Remote Control Door Lock Transmitter. This sends a Class 2 serial data message to the Body Control Module (BCM) which triggers the panic alarm. The parklamps and the horn alternately cycle ON and OFF for up to 2 minutes. If you turn the ignition switch to the RUN position or if you press the panic button while the panic alarm is active, the alarm immediately turns OFF. If the delayed off Automatic Lighting Control (ALC) function is active when you trigger the panic alarm, the ALC parklamp control is overridden in order to control the cycling of the parklamps. If you request the Remote Control Door Lock Receiver horn chirp while the panic alarm is triggered, the chirp request is ignored.

Rear Compartment Lid Release

The rear compartment lid release system allows you to release the rear compartment lid electrically in one of 2 different ways:

In order to operate the rear compartment lid release system, one of the following must be true:

Vehicle Theft Deterrent (VTD)

The red security indicator is a distributed function between the Body Control Module (BCM) and the instrument cluster. The BCM determines the status of the security indicator based on its internal Passlock® algorithm and what has been communicated to it from the Powertrain Control Module (PCM) Passlock® algorithm. The BCM then forwards a status of either OFF, ON or FLASH to the instrument cluster over the Class 2 serial data bus. If the indicator status is FLASH, the instrument cluster actually controls the flash rate/timing.

The SECURITY indicator shows whether the Passlock® data has passed. The BCM sends a message to turn the SECURITY indicator ON or OFF to the Instrument Panel Cluster (IPC) via the Class 2 serial data bus.

The SECURITY indicator is ON when the BCM is not in the auto-learn mode and either of the following conditions is true:

The SECURITY indicator flashes when either of the following conditions is true:

If the BCM is in a 10-minute tamper and the ignition switch is turned to the OFF position, the instrument cluster remains awake and flashes the SECURITY indicator until the BCM requests a status of OFF. The instrument cluster has a maximum wait time defined. The instrument cluster tests the security indicator bulb.

For further explanation of the Vehicle Theft Deterrent (VTD), refer to Theft Deterrent System.

Wake-up/Asleep States

Wake-ups are signals that turn ON the Body Control Module (BCM) and cause the BCM to begin active control and/or monitoring. The BCM wake-ups are as follows:

Once the ignition switch is turned OFF, a time-out period begins. The length of time before the timer expires depends on the accumulative vehicle mileage. If the mileage is under 24 km (15 mi), the vehicle is assumed to be in the plant or the dealership lot, and the time out period of 3 minutes is used. If the accumulative mileage is greater than 24 km (15 mi), the vehicle is assumed to be in the hands of the customer, and time out period of 20 minutes is used.