Part 2A

CHIME SYSTEMS
The Chime System is an integral part of the Body Control Module (BCM) and provides the driver with two types of chimes, Warning and Announcement. The BCM monitors its hardwired inputs and CCD bus messages to determine when a chime is needed. The Warning Chimes are a dual tone chime for the following conditions: Seat Belt Unbuckled, Exterior Lamps On, Key-In Ignition, Critical tire pressure, and Dome Lamps On. The Announcement Chime is a single tone chime to warn the driver when an instrument cluster gauge is out of range or a warning lamp is on. Refer to the General Information, System Description and Functional Operation for more information on the Instrument Cluster gauges and warning lamps.

During shipment (with the IOD fuse disconnected) the Warning and Announcement chimes will not work with the ignition key turned OFF.

Seat Belt Chime
The seat belt chime will sound for up to 8 seconds, when the ignition is turned ON and the driver's seat belt is unbuckled, as a reminder to the driver to buckle the seat belt. Buckling the driver's seat belt before the time out has expired will cause the chime to stop immediately. The seat belt lamp will stay on for 7 seconds even if the seat belt is buckled or stay on as long as the ignition key is on if the seat belt remains unbuckled.

Exterior Lamps On Chime
The Exterior Lamp On Chime will act as a warning to the driver that the exterior lights have been left on. If the ignition is OFF, the driver's door is open, and the park lamps or headlamps are ON, the chime will sound until one of the conditions is removed or until the battery protection timeout of 3 minutes.

Key-In Ignition Chime
The key-in Ignition Chime will act as a warning to the driver that the key has been left in the ignition. If the ignition is off and not in the accessory power position, the driver's door is open or ajar, and the key is in the ignition, the chime will sound until one of the conditions is removed or the battery protection timeout of 15 minutes has expired.

Courtesy Lamp On Chime
The Courtesy Lamp On Chime will act as a warning to the driver that the dome lamps have been left on. When the ignition is OFF, driver's door is open, and the dome lamps are ON, the chime will sound continuously until one of the conditions is removed or until the battery protection timeout of 15 minutes has expired.

Turn Signal On Chime
The Turn Signal On Chime will act as a warning to the driver that the turn signals have been left ON. When a level change is detected on the turn signal inputs to the BCM continuously for approximately 1 mile, and the vehicle speed is greater than 15 MPH, the chime will sound continuously until the turn signal inputs are no longer active. If vehicle speed drops below 15 MPH prior to the warning being activated the accumulated distance traveled will be reset. Chime rate is approximately 50 chimes per minute.

Airbag Warning Lamp Announcement Chime
The Airbag Warning Lamp is monitored by the BCM. If the engine exceeds 450 RPM for more than 10 seconds and the airbag warning lamp is ON, a single chime will be sounded. The chime will not be rearmed until the vehicle speed equals zero and the Airbag Warning Lamp is OFF.

Warning Lamp Announcement Chime
The Warning Lamp Announcement Chime will act as a warning to the driver to scan the instrument cluster to observe which lamp is illuminated. Whenever the check gauges, low fuel, low washer level, service engine soon, system voltage failure, or low tire pressure lamps are first illuminated, the chime will sound for one tone. If a door or the decklid is ajar, the chime will continue to sound until the item ajar is closed or the ignition is switched OFF.

The low tire pressure critical chime will sound with each flash of the low tire warning lamp.

During the first two seconds of the ignition on or until the seat belt warning chime ends, all announcement chimes will be consolidated into one warning announcement. This will occur two seconds after the seat belt warning chime ends. If a warning announcement should occur while a higher priority warning chime is in process, no additional warning lamp announcement chime will be given after the chime in process ends. All associated lamps will illuminate and the active chime will serve as the warning announcement.

In the case of the chime warning associated with the Service Engine Soon lamp, the chime will sound only the first illumination of this lamp. Any other condition that could normally activate the warning announcement associated with the service engine soon lamp will not reactivate the chime if the lamp is currently illuminated.

NOTE: If the CCD bus communication with the engine controller is lost, the BCM assumes a vehicle speed of 3 mph. This results in the door ajar warning tone being sounded immediately whenever a door becomes ajar.

DOOR AJAR SYSTEM
The door/deck ajar illuminated warning is accomplished by the words "DOOR" and "DECK" displayed on the odometer. The "DOOR" and "DECK" bulb check is performed at ignition on and consists of an odometer display segment test. The door ajar is controlled by a MIC message from the BCM. The "DECK" ajar message is controlled by the MIC that is hardwired directly to the decklid ajar switch. The decklid ajar is also wired to the BCM. The hood ajar switch is wired to the BCM for use in the vehicle theft alarm system and does not have a warning lamp.

EXTERIOR LIGHTING CONTROL
The headlamps and park lamps are controlled by external relays which are controlled by the body control module. The headlamp relays are located in the power distribution center and the parklamp relay is located in the micro relay center behind the glove box. When the park lamp switch is turned ON (signals as a ground) the BCM then grounds the park lamp relay to provide power to the park, tail and marker lamps. The park lamp power feed, which is controlled by the BCM, also provides back-up power to the BCM. In the event that the ignition is turned off with the park lamps still on, the BCM will function normally (as if the IOD had been reconnected) until the park lamps are turned OFF. When the headlamp switch is turned ON, (signals as a B+ feed) the BCM grounds low beam and high beam headlamp relay coils to turn ON the headlamps. However, the high beams will not turn ON until the dimmer switch is activated.

Headlamp Time Delay
The headlamp delay feature keeps the headlamps on for 60 seconds, giving the driver and passenger security when exiting the vehicle. It is activated by sequentially turning OFF the ignition, and then turning off the headlamps. The headlamps must be turned OFF within 45 seconds of the ignition transition to off, to activate the headlamp delay. Once the headlamp delay has started the headlamps will remain on for 60 seconds or until the park lamps (or headlamps) are cycled ON/OFF or the ignition is turned ON.

Battery Protection
If the park lamp or headlamp switch remains on for more than 3 minutes while the ignition is OFF, the headlamps and park lamps will be turned OFF by the BCM and the input causing the lamps to be on will be ignored until the condition is corrected. Once the 3 minute timeout has elapsed the BCM will enter sleep mode. This feature provides protection to avoid running the battery down in the event the customer fails to turn the lamps OFF.

INSTRUMENT CLUSTER (MIC)
The Prowler utilizes a 'smart' instrument cluster. The tachometer and the voltmeter gauges are hardwired and are not part of the instrument cluster self test routine which will be explained later. They cannot be actuated. As mentioned previously, the tach is hardwired directly to the PCM, the illumination circuit, however, is part of the instrument panel lighting circuit. The voltmeter is hardwired to the B (+) circuit through the ignition switch.

The cluster positions its gauges based on a message formulated by the BCM for gauge position. All the sensors that are responsible for a gauge message are hardwired to the BCM. The BCM then builds the message and sends it over the CCD bus where the cluster will receive the message, decode it, and position all the gauge pointers at their proper positions.

The cluster also contains hardwired and CCD bus controlled warning lamps. A hardwired lamp is usually supplied B (+) by the cluster and ground by the circuit that it monitors. Any circuit that has a lamp that is CCD bus controlled will be an input to the BCM, except the Airbag Lamp which receives it's CCD messages from the Airbag Control Module (ACM). If no messages are received from the ACM for 5 seconds the Airbag lamp will be turned ON.

There is an onboard self-test that can be actuated stand-alone or with the DRB III. During the self-test, the cluster will position all the gauges at predetermined calibration points, the CCD controlled lamps will be illuminated, as well as the segments of the LCD odometer. This allows verification of gauge operation, CCD operation, as well as a visual check of all the individual segments in the LCD odometer.

INTERIOR LIGHTING

Courtesy Lamp Control
The interior courtesy lamps located in the right and left foot well area, the rear view mirror and the ignition switch halo lamp are hardwired together and are controlled by the BCM. They can be activated by the dome lamp switch, by opening a door or by the RKE when it activates the BCM 30 second illuminated entry timer. The interior lamps will then fade to off over a 5 second period.

Reading Lamps
The reading lamps and control switches are mounted on the rear view mirror.

Interior Lamp Battery Protect Feature (Load Shedding)
To protect the battery from excessive current draw, the courtesy, halo, reading and glove box lamps are shut off after 15 minutes if they have been left ON or a door has been left ajar after the ignition key is removed from the ignition. This is accomplished by the BCM which removes ground from these lamps.

Instrument Panel Dimming
I/P dimming is accomplished using the body control module. The panel dimming level switch is read by the body control module and converted to a value that is sent over the CCD bus.

I/P Dimmer/Dome Lamp Switch
This switch is part of the headlamp switch. It is used to adjust the intensity of the instrument panel lighting. Instrument panel dome lamps can be requested by rotating the I/P illumination switch fully counterclockwise.

Illuminated Entry
Illuminated entry will be initiated when the customer enters the vehicle by unlocking the doors with the key fob, or with the key or by opening any door. Upon exiting the vehicle, if the lock button is pressed with a door open, illuminated entry will cancel when the door closes. If the vehicle is secure, and a remote keyless entry lock message is received, illuminated entry will cancel. If the doors are closed and the ignition switch is turned ON, the illuminated entry also cancels.

LOW TIRE PRESSURE WARNING SYSTEM (LTPW)
This system monitors tire pressure and provides warning via a low tire warning lamp and an audible tone(s) when a tire's pressure has fallen below a predefined threshold. There are two thresholds, they are "Tire Pressure Low" and "Tire Pressure Critical". The system only operates when the vehicle is moving above approximately 33 km/h (20 mph). Above this speed, the low tire pressure warning system will continuously monitor the air pressure in all four tires. The low tire pressure warning system will alert the driver in the event the air pressure falls below a threshold in one or more of the tires.

The LTPW System consists of:
- Low Tire Pressure Warning Module
- 4 Tire Pressure Sensor/Transmitters
- Body Control Module (BCM)
- Low Tire Pressure Warning Indicator

The system operates by monitoring a radio frequency (RF) transmission from Tire Pressure Sensor/Transmitters located in each wheel, and integrated with the valve stem. The transmitter is powered by a battery located inside the assembly. To extend the life of the battery, the transmitter does not send a signal to the module at vehicle speeds below approximately 33 km/h (20 mph). When the vehicle attains a speed of approximately 33 km/h (20 mph), the centrifugal force of the rotating wheel closes a roll switch (inside the transmitter) that powers up the circuitry.

Each transmitter has a unique identity (ID) code. The ID code allows the module to indicate to the driver, through the Low Tire Warning Indicator, that one of the tires has lost air pressure. The DRB III can be used to tell which tire pressure sensor/transmitter has failed or sensed a low tire pressure based on its ID code.

Verification that the LTPW system is operational must be performed during a road test, since the system is only operational when the vehicle is moving more than 33 km/h (20 mph). The DRB III must not be connected during the road test. The DRB III can be used following the road test to check whether or not signals were received by the LTPW module.