Part - 2

OPERATION

CRUISE INDICATOR

The cruise indicator indicates to the driver when the speed control system is ON, regardless of whether the speed control is engaged. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received by the cluster from the PCM over the CAN data bus.

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

- Cruise Indicator Lamp-On Message - Each time the cluster receives an electronic cruise indicator lamp-ON message from the PCM indicating the speed control system is ON, the cruise indicator is illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the PCM, or until the ignition switch status transitions to OFF, whichever occurs first.

The PCM continually monitors the speed control switches to determine the appropriate outputs to control the vehicle speed. The PCM then sends the proper lamp-ON or lamp-OFF message to the CCN.

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

ELECTRONIC STABILITY CONTROL INDICATORS

The ESC indicators give an indication to the vehicle operator of the Electronic Stability Control (ESC) system status. These indicators are controlled by transistors 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 indicators for about four seconds each time the ignition switch status transitions to ON, during the bulb test.

The ESC indicator and ESC OFF indicator LED units are completely controlled by the instrument cluster logic circuit, and that logic will only allow these indicators to operate when the instrument cluster receives a battery current input on the fused ignition output (run-start) circuit. Therefore, the ESC and ESC OFF indicator LED units will always be OFF when the ignition switch status is anything except ON or START. The LED units only illuminate when provided a path to ground by the instrument cluster transistors. The instrument cluster will turn ON the ESC indicators for the following reasons:

- ESC Indicator Lamp-On Message - Each time the cluster receives an electronic ESC indicator lamp-ON message from the CAB indicating that the ESC system has been activated, the ESC indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch status transitions to OFF, whichever occurs first.
- ESC Off Indicator Lamp-On Message - Each time the cluster receives an electronic ESC Off indicator lamp-ON message from the CAB indicating that the ESC system has been manually disabled, the ESC OFF indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch status transitions to OFF, 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 system has been manually disabled, an ESC OFF textual message will appear within the cluster electronic display unit. The ESC OFF textual message remains displayed 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 status transitions to OFF, whichever occurs first.
- ESC 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 textual warning request message from the CAB or FDCM, a WARNING! LIMIT SPEED textual message will appear within the cluster electronic display unit to accompany an ESC indicator that is illuminated solid. This message indicates that the CAB or FDCM has detected a problem in one of the ESC system circuits or components.

The CAB and FDCM continually monitors the ESC 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 system, the CAB, the FDCM, the CCN, the CAN data bus or the electronic communication related to the ESC or ESC Off 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 the instrument cluster logic circuit based upon cluster programming and electronic messages received by the cluster from the PCM over the CAN data bus.

The ETC indicator function of the cluster electronic 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 output (run-start) circuit. Therefore, the ETC indicator will always be OFF when the ignition switch status is anything except ON or START. 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 status transitions to OFF.

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, 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.

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 switch status transitions to ON, 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 output (run-start) circuit. Therefore, the LED will always be off when the ignition switch status is anything 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 status transitions to OFF, 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.

FOUR-WHEEL DRIVE LOW INDICATOR

The Four-Wheel Drive (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 output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch status is anything 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 status transitions to OFF, 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 electronic display unit 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.

FRONT 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 Totally Integrated Power Module (TIPM) 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 status. 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 TIPM 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 TIPM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.

The TIPM continually monitors electronic exterior lighting switch request messages from the CCN to determine the appropriate outputs to the front fog lamp relay. The TIPM 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 TIPM, 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

On base model vehicles, an ECO or ECO-on textual messages 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. On premium model vehicles, the fuel saver indicator (Economizer) messages will display below the outside temperature in the electronic display unit. These messages 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 electronic display menu.

This feature allows the vehicle operator to monitor when the vehicle is being driven in a fuel efficient manner and can be used to modify driving habits in order to increase fuel economy.

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 electronic 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 output (run-start) circuit. Therefore, the gas cap indication will always be OFF when the ignition switch status is anything 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 status transitions to OFF, 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.