Part 3

OPERATION

MALFUNCTION INDICATOR LAMP





The Malfunction Indicator Lamp (MIL) indicates to the vehicle operator that the PCM has recorded a DTC for an On-Board Diagnostics II (OBDII) emissions-related circuit or component malfunction. A transistor on the instrument cluster circuit board controls this indicator based upon cluster programming and electronic messages received by the cluster from the PCM over the CAN data bus.

The MIL LED is completely controlled by the instrument cluster logic circuit. That logic allows this indicator to operate only when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED is always off when the ignition switch is in any position except ON or START. The LED illuminates only when it is provided a path to ground by the instrument cluster transistor. The instrument cluster illuminates the MIL for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the indicator illuminates for about fifteen seconds as a bulb test. The entire bulb test is a function of the PCM.
- MIL Lamp-On Message - Each time the cluster receives a MIL lamp-on message from the PCM, the indicator illuminates. The indicator flashes on and off, or illuminates solid, as dictated by the PCM message. For some DTCs, if a problem does not recur, the PCM sends a lamp-off message automatically. Other DTCs may require that a fault be repaired and the PCM be reset before a lamp-off message is sent. For more information on the PCM, and the DTC set and reset parameters, Emissions Control - Operation.
- Communication Error - If the cluster receives no messages from the PCM for ten consecutive message cycles, the instrument cluster illuminates the MIL to indicate a loss of bus communication. The indicator remains controlled and illuminated by the cluster until a valid message is received from the PCM.
- Self Test - Each time the cluster is put through the self test, the MIL indicator illuminates during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The PCM continually monitors the fuel and emissions system circuits and sensors to determine if the system is in good operating condition. The PCM then sends the proper lamp-on or lamp-off message to the instrument cluster. For further diagnosis of the MIL or the instrument cluster circuitry that controls the LED, Testing and Inspection. If the instrument cluster turns on the MIL after the bulb test, it may indicate that a malfunction has occurred and that the fuel and emissions systems may require service. The MIL is serviced with the instrument cluster.

SEAT BELT INDICATOR





The seat belt indicator indicates to the vehicle operator the status of the driver side front seat belt. A transistor on the instrument cluster circuit board controls this indicator based upon cluster programming and a hardwired input from the seat belt switch in the driver side front seat belt retractor through the seat belt indicator driver circuit.

The seat belt indicator also includes a programmable enhanced seat belt reminder or "belt-minder" feature that is enabled when the vehicle is shipped from the factory. This beltminder feature is disabled and enabled by the customer using a specific programming event sequence, or by the dealer using a diagnostic scan tool.

The seat belt indicator LED is completely controlled by the instrument cluster logic circuit. That logic allows this indicator to operate only when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED is always off when the ignition switch is in any position except ON or START. The LED illuminates only when it is provided a path to ground by the instrument cluster transistor. The instrument cluster illuminates the seat belt indicator for the following reasons:

- Bulb Test - Each time the cluster receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator illuminates as a seat belt reminder for about six seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. This reminder function will occur regardless of the status of the seat belt switch input to the cluster.
- Driver Side Front Seat Belt Not Buckled - Beltminder Active - Following the seat belt reminder function, each time the cluster detects an open circuit on the seat belt indicator driver circuit (seat belt switch open = seat belt unbuckled) with the ignition switch in the ON or START position, the indicator illuminates. In addition, if the driver side front seat belt remains unbuckled after the conclusion of the seat belt reminder function, with the vehicle speed greater than about 10 kilometers-per-hour (6.2 miles-per-hour), the seat belt indicator begins to cycle between flashing on and off for three seconds, then lighting solid for two seconds. The seat belt indicator continues to cycle between flashing and solid illumination for thirteen complete cycles, until the seat belt indicator driver input to the cluster is closed to ground (seat belt switch closed = seat belt buckled), or until the ignition switch is turned to the OFF position, whichever occurs first.
- Driver Side Front Seat Belt Not Buckled - Beltminder Inactive - Following the seat belt reminder function, each time the cluster detects an open circuit on the seat belt indicator driver circuit (seat belt switch open = seat belt unbuckled) with the ignition switch in the ON or START position, the indicator illuminates. The seat belt indicator remains illuminated until the seat belt indicator driver input to the cluster is closed to ground (seat belt switch closed = seat belt buckled), or until the ignition switch is turned to the OFF position, whichever occurs first.
- Self Test - Each time the cluster is put through the self test, the seat belt indicator turns on and off during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The seat belt switch is connected in series between ground and the seat belt indicator driver input to the instrument cluster. The seat belt switch input to the instrument cluster circuitry may be diagnosed using conventional diagnostic tools and methods. Refer to the appropriate wiring information. The seat belt indicator is serviced with the instrument cluster.

SECURITY INDICATOR





The security indicator indicates to the vehicle operator when the Vehicle Theft Security System (VTSS) is arming or is armed. On models equipped with the Sentry Key Immobilizer System (SKIS), the security indicator also indicates to the vehicle operator the status of the SKIS. A transistor on the instrument cluster circuit board controls this indicator based upon cluster programming, hardwired inputs to the cluster from the various security system components, electronic messages received by the cluster from the Sentry Key REmote Entry Module (SKREEM) over the CAN data bus.

The security indicator LED is completely controlled by the instrument cluster logic circuit. That logic allows this indicator to operate only when the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED illuminates regardless of the ignition switch position. The LED illuminates only when it is provided a path to ground by the instrument cluster transistor. The instrument cluster illuminates the security indicator for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the security indicator illuminates for about three seconds as a bulb test. The entire bulb test is a function of the SKREEM.
- VTSS Indication - During the sixteen-second VTSS arming function, the cluster flashes the security indicator on and off repeatedly at a steady, fast rate to indicate that the VTSS is in the process of arming. Following successful VTSS arming, the cluster flashes the security indicator on and off continuously at a slower rate to indicate that the VTSS is armed. The security indicator continues flashing at the slower rate until the VTSS is disarmed or triggered. If the VTSS has alarmed and rearmed, the cluster flashes the security indicator at a steady, slow rate for about thirty seconds after the VTSS is disarmed.
- SKIS Lamp-On Message - Each time the cluster receives a SKIS lamp-on message from the SKREEM, the security indicator illuminates. The indicator flashes on and off, or illuminates solid, as dictated by the SKREEM message. The indicator remains illuminated solid or continues to flash until the cluster receives a SKIS lamp-off message from the SKREEM, or until the ignition switch is turned to the OFF position, whichever occurs first. For more information on the SKIS and the security indicator control parameters, Vehicle Theft Security System - Operation.
- Communication Error - If the cluster receives no SKIS lamp-on or lamp-off message from the SKREEM for ten consecutive message cycles, the instrument cluster illuminates the security indicator. The cluster controls and illuminates the indicator until a valid SKIS lamp-on or lamp-off message is received from the SKREEM.
- Self Test - Each time the instrument cluster is put through the self test, the security indicator turns on and off during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The instrument cluster circuitry controls the security indicator whenever the ignition switch is in the OFF position and the VTSS is arming, armed, or alarming. Whenever the ignition switch is in the ON or START positions, the SKREEM performs a self-test to determine if the SKIS is in good operating condition and whether a valid key is present in the ignition lock cylinder. The SKREEM then sends the proper lamp-on or lamp-off message to the instrument cluster. For further diagnosis of the security indicator or the instrument cluster circuitry that controls the indicator, Testing and Inspection. If the instrument cluster flashes the security indicator upon ignition ON, or illuminates the security indicator solid after the bulb test, a SKIS malfunction has occurred or the SKIS is inoperative. The security indicator is serviced with the instrument cluster.

TRACTION CONTROL INDICATOR





The traction control indicator indicates to the vehicle operator that the electronic Traction Control System (TCS) has been activated. The instrument cluster circuit board controls this indicator based upon cluster programming and electronic messages received by the cluster from the CAB over the CAN data bus.

The traction control indicator is completely controlled by the instrument cluster logic circuit. That logic allows this indicator to operate only when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the indicator is always off when the ignition switch is in any position except ON or START. The indicator illuminates only when it is switched to ground by the instrument cluster circuitry. The instrument cluster illuminates the traction control indicator for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the traction control indicator illuminates for about four seconds as a bulb test. The entire bulb test is a function of the CAB.
- Traction Control Lamp-On Message - Each time the cluster receives a traction control lamp-on message from the CAB indicating that the TCS has been activated, the traction control indicator illuminates. The indicator remains illuminated until the cluster receives a traction control lamp-off message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Self Test - Each time the cluster is put through the self test, the traction control indicator turns on and off during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The CAB continually monitors the traction control switch to determine the proper outputs to the components of the Antilock Brake System (ABS). The CAB then sends the proper traction control lamp-on and lamp-off messages to the instrument cluster. For further diagnosis of the traction control indicator or the instrument cluster circuitry that controls the indicator, Testing and Inspection. The traction control indicator is serviced with the instrument cluster.

TURN SIGNAL INDICATORS





The turn signal indicators indicate to the vehicle operator that a turn signal (left or right indicator flashing) or the hazard warning (both left and right indicators flashing) has been selected and is operating. The transistors on the instrument cluster electronic circuit board controls these indicators. Control is based upon the electronic messages received from the FCM over the CAN data bus.

Each turn signal indicator LED is completely controlled by the instrument cluster logic circuit. That logic allows this indicator to operate only when the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, each LED illuminates regardless of the ignition switch position. The LED illuminates only when it is provided a path to ground by the instrument cluster transistor. The instrument cluster illuminates the turn signal indicators for the following reasons:

- Turn Signal-On Input - The Steering Control Module (SCM) sends a data bus message to the FCM to turn on the turn signals. The FCM sends a message to the CCN to illuminate the appropriate electronic turn signal switch indicator. The FCM controls the output and the flash rate for both the right and left turn signal lamps and sends this message to the CCN. The CCN controls the illumination and flash rate of the right or left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the CCN electronic circuit board that emulates the sound emitted by a conventional turn signal flasher. The turn signals and the turn signal indicators continue to flash on and off until the cluster receives a turn signal-off input from the multi-function switch, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Hazard Warning-On Input - The FCM controls the turn signal flashers. The SCM sends a data bus message to the FCM and the FCM responds by controlling a battery voltage output and the flash rate for each of the right and left turn signal lamps. The FCM sends the appropriate electronic messages back to the CCN. It controls the illumination and flash rate of the right and left turn signal indicators, as well as the click rate of an electromechanical relay soldered onto the CCN electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The turn signals and the turn signal indicators continue to flash on and off until the cluster receives a hazard warning-off input over the can data bus.
- Lamp Out Mode - The instrument cluster sends electronic turn signal on and off messages to the FCM over the CAN data bus, and the FCM flashes the appropriate exterior turn signal lamps. If the FCM detects an inoperative turn signal lamp or circuit, it increases the flash rate for the remaining operative turn signals and sends an electronic message back to the instrument cluster. The instrument cluster then increases the flash rate of the turn signal indicator(s) and the clicking rate of the electromechanical relay to provide an indication of the problem to the vehicle operator.
- Self Test - Each time the cluster is put through the self test, the turn signal indicators turns on and off during the bulb check portion of the test to confirm the functionality of each LED and the cluster control circuitry.

The instrument cluster continually monitors the multi-function switch and electronic messages from the FCM to determine the proper turn signal and hazard warning system control. For further diagnosis of the turn signal indicators or the instrument cluster circuitry that controls the indicators, Testing and Inspection. The turn signal indicators are serviced with the instrument cluster.

CLUSTER ILLUMINATION

The CCN has a single electro-luminescent lamp that provides cluster back lighting whenever the parking lamps are illuminated The illumination intensity of this lamp is adjusted when the interior lighting thumbwheel on the headlamp switch is rotated (down to dim, up to brighten). The CCN monitors a resistor multiplexed input from the headlamp switch on a dimmer input circuit. In response to that input, the CCN varies the Pulse Width Modulated (PWM) voltage from 5.6 volts to 13.5 volts rms.

The CCN uses this PWM output to control the illumination intensity of the electro-luminescent cluster illumination lamp and the VFD units on the CCN circuit board. It then provides a synchronized PWM output on various hardwired fused panel lamps dimmer switch signal circuits to control and synchronize the illumination intensity of other incandescent illumination lamps in the vehicle. The CCN also transmits electronic dimming level messages over the CAN data bus to other electronic modules in the vehicle to control and synchronize the illumination intensity of their VFD units to that of the CCN VFD units.

In addition, the thumbwheel on the headlamp switch has a parade mode position to provide a parade or funeral mode. The CCN monitors the request for this mode from the headlamp switch, then transmits an electronic dimming level message to illuminate all VFD units in the vehicle at full (daytime) intensity for easier visibility when driving in daylight with the exterior lighting illuminated.

ELECTRONIC VEHICLE INFORMATION CENTER

The following modes allow the driver to access and display the driver-interactive features:

TRIP MODE

Provides a choice of units displayed in English or metric. The following information is displayed at the top of the screen: Average MPG, distance to empty (DTE), Trip A and Trip B odometers, and elapsed time. The odometer is displayed at the bottom of the screen. If warnings exist, they replace the odometer in the display. The driver scrolls to view multiple warnings.

COMPASS, TEMPERATURE AND AUDIO MODE

Compass heading and outside temperature are displayed at the top of the screen. On the lower half of the screen the audio mode is displayed along with the odometer.

TELEPHONE MODE

Provides the following information and features for the optional hands-free communications system:

- Phone status: idle, voice mail, roaming, battery strength and signal strength in increments of 20 percent.
- Call status: Incoming call, connecting, connected, air time in minutes and seconds, call ended, busy, call failed, roaming and no phone connection.
- Caller ID phone number display.

NAVIGATION MODE

Displays turn-by-turn directions that appear in the display as the vehicle approaches a designated turn within a programmed route.

PERSONAL SETTINGS MODE

Allows the driver to set and recall features when the transmission is in PARK.

SYSTEM STATUS MODE

Displays warnings and user interaction messages. Initial warnings are displayed full-screen for three seconds, then override the odometer and show text warnings on the bottom line of the display. Critical text warnings are displayed until the failure is corrected. Non-critical text warnings are displayed for 60 seconds. The driver scrolls to view multiple messages. A single chime sounds for all warnings.

For a more detailed operation of the EVIC Electronic Vehicle Information Center - Operation.