Part - 2

OPERATION

DOOR AJAR INDICATOR

The ajar indicators give an indication to the vehicle operator that one or more of the passenger compartment doors, the hood, the liftgate or the liftgate flip-up glass may be open or not completely latched. These indicators are controlled by the instrument cluster logic circuit based upon cluster programming and hard-wired inputs received by the cluster from the door, liftgate and liftgate flip-up glass ajar switches as well as from electronic hood ajar switch status messages received over the CAN data bus from the Front Control Module (FCM).

The ajar indicator function of the LCD display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LCD ajar indications can occur regardless of the ignition switch position. The instrument cluster will turn ON an ajar indicator for the following reasons:

- Ajar Switch Input or Status Message - Each time the cluster receives a door, liftgate or liftgate flip-up glass ajar switch input indicating that a door, the liftgate or the liftgate flip-up glass or any combination of these is open or not completely latched with the ignition switch in any position, the appropriate ajar textual message and icons will be illuminated. A hood ajar indication happens only with the ignition switch in the ON or START positions. If the cluster detects a vehicle speed input greater than zero (kilometers or miles-per-hour) while the ignition switch is in the ON or START positions, the ajar indication will be accompanied by a single chime tone. When the ignition switch is in any position except ON or START, any and all ajar indications will time out after about five minutes.

The instrument cluster continually monitors the door, liftgate and liftgate flip-up glass ajar switches to determine the status of the doors, liftgate and liftgate flip-up glass. The FCM continually monitors the status of the hood ajar switch, then sends the proper electronic hood ajar switch status message to the CCN.

For proper diagnosis of the door, hood, liftgate and liftgate flip-up glass ajar switches and circuits, the FCM, the CCN, the CAN data bus or the electronic communication related to ajar indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

ELECTRONIC THROTTLE CONTROL INDICATOR

The Electronic Throttle Control (ETC) indicator gives an indication to the vehicle operator when the ETC system, or a circuit or component of the system is ineffective. The ETC indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM over the CAN data bus. The CCN will illuminate the ETC indicator for about fifteen seconds each time the ignition is turned to the ON position, during the bulb test.

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

- ETC Indicator Lamp-On Message - Each time the cluster receives an electronic ETC indicator lamp-ON message from the PCM, the ETC indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the PCM message. The indicator remains illuminated solid or continues to flash for about 12 seconds or until the cluster receives a lamp-OFF message from the PCM, whichever is longer. If the indicator is illuminated solid with the engine running the vehicle will usually remain drivable. If the indicator is flashing with the engine running the vehicle may require towing. A flashing indicator means the ETC system requires immediate service. The indicator will be extinguished when the ignition switch is turned to the OFF position.

The PCM continually monitors the ETC system circuits and sensors to decide whether the system is in good operating condition. The PCM then sends the proper lamp-ON or lamp-OFF message to the CCN. If the PCM sends a lamp-ON message after the bulb test, it indicates that the PCM has detected an ETC system malfunction or that the ETC system is ineffective. The PCM will store a DTC for any malfunction it detects. Each time the ETC indicator fails to illuminate due to an open or short in the cluster ETC indicator circuit, the cluster sends a message notifying the PCM of the condition, then the CCN and the PCM will each store a DTC.

For proper diagnosis of the ETC system, the PCM, the CCN, the CAN data bus or the electronic communication related to ETC indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

ENGINE TEMPERATURE INDICATOR

The engine temperature indicator gives an indication to the vehicle operator when the engine temperature gauge reading reflects a condition requiring immediate attention. This indicator is controlled by a transistor on the CCN circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The CCN will illuminate the engine temperature indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test.

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

- Engine Temperature High Message - Each time the CCN receives a message from the PCM indicating the engine coolant temperature is above about 252° F (122° C), the engine temperature indicator will be illuminated and a single chime tone is sounded. The indicator remains illuminated until a message from the PCM indicating that the engine coolant temperature is below about 246° F (119° C) is received, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature will only repeat during the same ignition cycle if the engine temperature indicator is cycled off and then on again by the appropriate engine temperature messages from the PCM.

The PCM continually monitors the engine coolant temperature sensor to determine the engine operating temperature. The PCM then sends the proper engine coolant temperature messages to the CCN. If the CCN turns on the engine temperature indicator due to a high engine temperature gauge reading, it may indicate that the engine or the engine cooling system requires service.

ESC/BAS INDICATOR

The ESC/BAS indicator gives an indication to the vehicle operator when the Electronic Stability Control (ESC)/Brake Assist System (BAS) has been activated. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the CAB and the Final Drive Control Module (FDCM) over the CAN data bus. The CCN will illuminate the ESC/BAS indicator for about four seconds each time the ignition is turned to the ON position, during the bulb test.

The ESC/BAS indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the ESC/BAS indicator for the following reasons:

- ESC/BAS Indicator Lamp-On Message - Each time the cluster receives an electronic ESC/BAS indicator lamp-ON message from the CAB indicating that the ESC/BAS system has been activated, the ESC/BAS indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
- ESC Off Textual Message - Each time the cluster receives an electronic ESC OFF indicator lamp-ON message from the CAB indicating that the ESC/BAS system has been manually disabled, an ESC OFF textual message will appear within the cluster re-configurable dot matrix display. The ESC OFF textual message remains displayed until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
- ESC/BAS Textual Warning Message - When the CAB or FDCM detects certain monitored fault conditions, it will send electronic messages requesting the cluster display a textual warning message. Each time the cluster receives an electronic ESC/BAS textual warning request message from the CAB or FDCM, a WARNING! LIMIT SPEED textual message will appear within the cluster re-configurable dot matrix display to accompany an ESC/BAS indicator that is illuminated solid. This message indicates that the CAB or FDCM has detected a problem in one of the ESC/BAS system circuits or components.

The CAB and FDCM continually monitors the ESC/BAS circuits and sensors to decide whether the system is in good operating condition and the proper outputs to the components of the system. The CAB or FDCM then sends the proper lamp-ON or lamp-OFF message to the CCN.

For proper diagnosis of the ESC/BAS system, the CAB, the FDCM, the CCN, the CAN data bus or the electronic communication related to the ESC/BAS indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

FOG LAMP INDICATOR

The front fog lamp indicator gives an indication to the vehicle operator whenever the front fog lamps are illuminated. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Front Control Module (FCM) over the CAN data bus.

The front fog lamp indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the front fog lamp indicator for the following reasons:

- Front Fog Indicator Lamp-On Message - Each time the cluster receives an electronic front fog indicator lamp-ON message from the FCM indicating the front fog lamps are turned ON, the front fog lamp indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the FCM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.

The FCM continually monitors electronic exterior lighting switch request messages from the CCN to determine the appropriate outputs to the front fog lamp relay. The FCM activates or deactivates the front fog lamp relay then sends the proper lamp-ON or lamp-OFF message back to the CCN.

For proper diagnosis of the front fog lamp system, the FCM, the CCN, the CAN data bus or the electronic communication related to front fog lamp indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

FUEL SAVER INDICATOR - ECONOMIZER (ECO / ECO-ON)

The ECO message will display below the outside temperature in the EVIC display. The message will appear whenever the vehicle is driven in a fuel efficient manner, if the feature is turned ON using the customer programmable feature within the EVIC display menu.

On base model vehicle, an ECO or ECO-on message will be displayed within the odometer display when selected by the vehicle operator. The fuel saver feature can be selected by pressing the odometer push-button and toggling through the menu.

This feature allows the vehicle operator to monitor when they are driving in a fuel efficient manner, and it can be used to modify driving habits in order to increase fuel economy.

4WD LOW INDICATOR

The 4WD low indicator gives an indication to the vehicle operator when the electronic transfer case has been shifted into the 4WD low mode. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Final Drive Control Module (FDCM) over the CAN data bus.

The 4WD low indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the 4WD low indicator for the following reasons:

- 4WD Low Indicator Lamp-On Message - Each time the cluster receives an electronic 4WD low indicator lamp-ON message from the FDCM, the indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the FDCM message. The indicator remains illuminated until the cluster receives a lamp-OFF message from the FDCM, or until the ignition switch is turned to the OFF position, whichever occurs first.
- 4WD Low Shift Procedure Textual Warning Messages - When the FDCM detects an attempt to shift the transfer case into or out of the 4WD low mode using an improper shift sequence, it will send an electronic message requesting the cluster display a textual warning message. Each time the cluster receives a textual warning request message from the FDCM, a CHECK SHIFT PROCEDURE textual message will appear within the cluster re-configurable dot matrix display to accompany a flashing 4WD low indicator.

The FDCM continually monitors the electronic transfer case through the transfer case shift motor/mode sensor assembly to determine when the 4WD low mode is engaged. The FDCM then sends the proper lamp-ON or lamp-OFF message to the CCN.

For proper diagnosis of the transfer case shift motor/mode sensor, the FDCM, the CCN, the CAN data bus or the electronic communication related to 4WD low indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

4WD NEUTRAL INDICATOR

The 4WD neutral indicator gives an indication to the vehicle operator when the electronic transfer case has been shifted into the 4WD neutral mode. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Final Drive Control Module (FDCM) over the CAN data bus.

The 4WD neutral indicator function of the LCD display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LCD 4WD neutral indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the 4WD neutral indicator for the following reasons:

- 4WD Neutral Indicator Lamp-On Message - Each time the cluster receives an electronic 4WD neutral indicator lamp-ON message from the FDCM, the indicator will be illuminated. The indicator remains illuminated for about five seconds, until the cluster receives a lamp-OFF message from the FDCM, until the cluster arbitrator logic determines that another display request has priority, or until the ignition switch is turned to the OFF position, whichever occurs first.

The FDCM continually monitors the electronic transfer case through the transfer case shift motor/mode sensor assembly to determine when the 4WD neutral mode is engaged. The FDCM then sends the proper lamp-ON or lamp-OFF message to the CCN.

For proper diagnosis of the transfer case shift motor/mode sensor, the FDCM, the CCN, the CAN data bus or the electronic communication related to 4WD neutral indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

GAS CAP INDICATOR

The gas cap indicator gives an indication to the vehicle operator when there is a gross leak detected in the on-board fuel vapor recovery system. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received over the CAN data bus from the PCM.

The gas cap indicator function of the LCD display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LCD gas cap indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the gas cap indicator for the following reasons:

- Gas Cap Indicator Lamp-On Message - Each time the cluster receives an electronic gas cap indicator lamp-ON message from the PCM indicating there is a gross leak in the vapor recovery system, the gas cap indicator will be displayed. The indicator remains displayed until the cluster receives a lamp-OFF message from the PCM, until the cluster arbitrator logic determines that another display request has priority, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM continually monitors the on board vapor recovery system to determine whether there are air leaks in the system. The PCM then sends the proper lamp-ON or lamp-OFF message to the CCN. If the CCN turns ON the gas cap indicator due to a monitored gross leak in the vapor recovery system, it may indicate that the gas cap has been removed or is improperly installed.

For proper diagnosis of the on board vapor recovery system, the PCM, the CCN, the CAN data bus or the electronic communication related to gas cap indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

HIGH BEAM INDICATOR

The high beam indicator gives an indication to the vehicle operator whenever the headlamp high beams are illuminated. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received from the Front Control Module (FCM) over the CAN data bus.

The high beam indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the high beam indicator for the following reasons:

- High Beam Indicator Lamp-On Message - Each time the cluster receives an electronic high beam indicator lamp-ON message from the FCM the high beam indicator will be illuminated. The high beam indicator remains illuminated until the cluster receives a lamp-OFF message from the FCM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.

The FCM continually monitors electronic messages from the CCN and the SmartBeam(R) module on vehicles so equipped to determine the proper headlamp beam control. The FCM activates or deactivates the headlamp high beams then sends the proper lamp-ON or lamp-OFF message back to the CCN.

For proper diagnosis of the SmartBeam(R) module, the FCM, the CCN, the CAN data bus or the electronic communication related to high beam indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.

HILL DESCENT INDICATOR

The hill descent indicator gives an indication to the vehicle operator when the QuadraDrive four-wheel drive transfer case gear selector is in the 4WD LOW position and the hill descent control push button in the instrument panel switch pod has been depressed to turn the feature ON. This feature uses the grade sensing logic of the CAB to sense the vehicle is descending a hill and employs the brake system to automatically control the hill descent speed of the vehicle. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received over the CAN data bus from the CAB.

The hill descent indicator function of the LCD display unit is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LCD hill descent indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the hill descent indicator for the following reasons:

- Hill Descent Indicator Lamp-On Message - Each time the cluster receives an electronic hill descent indicator lamp-ON message from the CAB, the indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, until the cluster arbitrator logic determines that another display request has priority, or until the ignition switch is turned to the OFF position, whichever occurs first.

The CAB continually monitors electronic message inputs from the Final Drive Control Module (FDCM) and the CCN to determine the status of the QuadraDrive four-wheel drive system and the hill descent control switch, then monitors its own internal grade sensing logic to determine when the hill descent mode should be engaged. The CAB then sends the proper lamp-ON or lamp-OFF message to the CCN.

For proper diagnosis of the hill descent control switch, the FDCM, the CAB, the CCN, the CAN data bus or the electronic communication related to hill descent indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.