Part 3

OPERATION

SEATBELT INDICATOR

The seatbelt indicator gives an indication to the vehicle operator of the status of the front seat belts. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic driver side and passenger side front seat belt switch status messages received over the CAN data bus.

The seatbelt indicator also includes a programmable enhanced seatbelt reminder or BELTMINDER feature that is enabled when the vehicle is shipped from the factory. This BELTMINDER feature can be disabled and enabled by the customer using a specific programming event sequence, or by the dealer using a diagnostic scan tool.

The seatbelt 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 seatbelt indicator for the following reasons:

- Seatbelt Reminder Function - Each time the cluster receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator will be illuminated as a seatbelt 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 seatbelt switch inputs to the cluster.
- Front Seatbelt Not Buckled Message - Beltminder Active - Following the seatbelt reminder function, each time the cluster receives an electronic driver side or passenger side front seat belt unbuckled status message with the ignition switch in the START or ON positions, the indicator will be illuminated. In addition, if a front seat belt remains unbuckled about 4 seconds after the conclusion of the seatbelt reminder function, the seatbelt indicator will begin to cycle between flashing ON and OFF for 3 seconds, then lighting solid for 2 seconds. The seatbelt indicator will continue to cycle between flashing and solid illumination for 13 complete cycles, until electronic driver side and passenger side front seat belt buckled status messages are received, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Front Seatbelt Not Buckled Message - Beltminder Inactive - Following the seatbelt reminder function, each time the cluster receives an electronic driver side or passenger side front seat belt unbuckled status message with the ignition switch in the START or ON positions, the indicator will be illuminated. The seatbelt indicator remains illuminated until electronic driver side and passenger side front seat belt buckled status messages are received, or until the ignition switch is turned to the OFF position, whichever occurs first.

The driver side seat belt switch is connected in series between ground and the seat belt switch sense circuit input to the TIPM, while the passenger side seat belt switch is connected between an output and an input of the Occupant Restraint Controller (ORC). The ORC also monitors inputs from the Occupant Classification Module (OCM) to determine whether the passenger side front seat is occupied. The TIPM and the ORC continually monitor these inputs, then send the proper status messages to the CCN over the CAN data bus.

SECURITY INDICATOR

The security indicator gives an indication to the vehicle operator when the Vehicle Theft Security System (VTSS) is arming or is armed. On vehicles equipped with the Sentry Key Immobilizer System (SKIS), the security indicator also gives an indication to the vehicle operator of the status of the SKIS. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming, and electronic security indicator request messages received by the cluster from the TIPM or the Sentry Key REmote Entry Module (SKREEM) (also known as the Wireless Control Module/WCM) over the CAN data bus. Each time the ignition switch is turned to the ON position the security indicator illuminates for about two seconds as a bulb test. The entire bulb test is a function of the SKREEM.

The security 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. Depending upon the programmed condition, the indicator can be illuminated solid, flashed at a slow rate (0.5 Hertz, 12.5 percent duty cycle), or flashed at a fast rate (1 Hertz, 50 percent duty cycle). The instrument cluster will turn ON the security indicator for the following reasons:

- Security Indicator Lamp-On Message - During the 16 second VTSS arming function, the TIPM will request the cluster flash 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 TIPM will request the cluster flash 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 TIPM will request the cluster flash the security indicator at a steady, slow rate for about 30 seconds after the VTSS is disarmed.
- SKIS Indicator Lamp-On Message - Each time the cluster receives an electronic SKIS indicator lamp-ON message from the SKREEM, the security indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the SKREEM message. The indicator remains illuminated solid or continues to flash until the cluster receives a 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 lamp-ON or lamp-OFF messages from the TIPM or the SKREEM for 10 consecutive message cycles, the security indicator is illuminated by the instrument cluster. The indicator remains controlled and illuminated by the cluster until a valid lamp-ON or lamp-OFF message is received from the SKREEM.

The TIPM sends electronic security indicator request messages to control 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 decide whether 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 CCN. If the cluster flashes the security indicator upon ignition ON, or turns ON the security indicator solid after the bulb test, it indicates that a SKIS malfunction has occurred or that the SKIS is ineffective.

TRACTION CONTROL INDICATOR

The traction control indicator gives an indication to the vehicle operator when the Electronic Stability Control (ESC) system has been activated. This indicator is controlled by the CCN logic circuit based upon cluster programming and electronic messages received from the CAB over the CAN data bus. The logic circuit 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 indicator will always be OFF when the ignition switch is in any position except ON or START. The indicator only illuminates when it is provided a path to ground by the cluster circuitry.

The indicator will be illuminated for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the traction control indicator is illuminated for about four seconds as a bulb test. The bulb test is a function of the CAB.
- Traction Control Indicator Lamp-On Message - Each time the cluster receives an electronic traction control indicator lamp-ON message from the CAB indicating that the ESC has been activated, the traction control indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the CAB message. The indicator remains illuminated solid or continues to flash 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.

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 lamp-ON or lamp-OFF message to the CCN.

TRACTION CONTROL OFF INDICATOR

The traction control OFF indicator gives an indication to the vehicle operator when the Electronic Stability Control has been deactivated. This indicator is controlled by the CCN logic circuit based upon cluster programming and electronic messages received from the CAB over the CAN data bus. The logic circuit 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 indicator will always be OFF when the ignition switch is in any position except ON or START. The indicator only illuminates when it is provided a path to ground by the cluster circuitry.

The indicator will be illuminated for the following reasons:

- Bulb Test - Each time the ignition switch is turned to the ON position the traction control indicator is illuminated for about four seconds as a bulb test. The bulb test is a function of the CAB.
- Traction Control Full Off Textual Message - Each time the cluster receives an electronic Traction Control Full OFF indicator lamp-ON message from the CAB indicating that the ESC system has been manually disabled. The Traction Control OFF 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.
- ESP Permanent Disable Textual Message - Each time the cluster receives an electronic ESP Permanent Disable message from the CAB indicating that the ESC system has been permanently disabled.

The CAB 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 then sends the proper lamp-ON or lamp-OFF message to the CCN.

TRANSMISSION RANGE INDICATOR

The electronic gear selector indicator gives an indication to the vehicle operator of the transmission gear that has been selected with the automatic transmission gear selector lever. This indicator is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received from the Powertrain Control Module (PCM) over the CAN data bus.

The gear selector indicator information is displayed by the odometer Vacuum Fluorescent Display (VFD) unit soldered onto the instrument cluster electronic circuit board, and the VFD will not display the gear selector indicator information after the ignition switch is turned to the OFF position. Each time the cluster is disconnected from battery current for more than about five minutes, it must configure itself for the automatic transmission type that is in the vehicle once it is reconnected to battery current. The instrument cluster circuitry operates the gear selector indicator to provide the following features:

- Selected Gear Message - Each time the cluster receives an electronic selected gear message from the PCM, a box will be illuminated around the appropriate character in the gear selector indicator. The box will remain illuminated until the cluster receives a different selected gear message, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - If the cluster fails to receive a selected gear message from the PCM within three seconds, the instrument cluster circuitry will display all gear selector positions boxed (selected) until a valid selected gear message is received or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM continually monitors a hard-wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the CCN.

TRANSMISSION TEMPERATURE INDICATOR

The transmission over-temperature indicator gives an indication to the vehicle operator when the transmission fluid temperature is excessive, which may lead to accelerated transmission component wear or failure. 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 Powertrain Control Module (PCM) over the CAN data bus. Each time the ignition switch is turned to the ON position the transmission over temperature indicator is illuminated for about two seconds as a bulb test.

The transmission over-temperature indicator LED is completely controlled by the instrument cluster logic circuit. This logic only allows the indicator to operate 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 only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster turns on the transmission over-temperature indicator for the following reasons:

- Trans Over-Temp Indicator Lamp-On Message - Each time the cluster receives an electronic transmission over temp indicator lamp-on message from the PCM indicating that the transmission fluid temperature is 135 °C (275 °F) or higher, the indicator illuminates and a single chime tone is sounded. The indicator remains illuminated until the cluster receives a lamp-off message from the PCM, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature only repeats during the same ignition cycle if the indicator is cycled off and then on again by the appropriate lamp-on and lamp-off messages from the PCM.

The PCM continually monitors the transmission temperature sensor to determine the transmission operating condition. The PCM then sends the proper lamp-on or lamp-off message to the CCN. If the instrument cluster illuminates the transmission over temperature indicator due to a high transmission oil temperature condition, it may indicate that the transmission or the transmission cooling system are being overloaded, or that they require service. For further diagnosis of the transmission over-temperature indicator or the instrument cluster circuitry that controls the LED, Instrument Cluster.

TURN SIGNAL INDICATORS

The turn signal indicators give an indication to the vehicle operator that the turn signal (left or right indicator flashing) or hazard warning (both left and right indicators flashing) have been selected and are operating. These indicators are controlled by transistors on the instrument cluster electronic circuit board based upon the cluster programming and electronic messages received from the TIPM over the CAN data bus.

Each turn signal 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, each 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 turn signal indicators for the following reasons:

- Turn Signal Indicator Lamp-On Message - Each time the cluster receives an electronic right or left turn signal-ON message from the TIPM over the CAN data bus, the appropriate turn signal indicator will be flashed ON and OFF. The TIPM also sends the appropriate electronic message to the cluster to control the flash rate of the turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the cluster electronic circuit board that emulates the sound emitted by a conventional turn signal flasher. The turn signal indicators continue to flash ON and OFF until the cluster receives a lamp-OFF message from the TIPM, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Hazard Warning Indicator Lamp-On Message - Each time the cluster receives an electronic hazard warning-ON message from the TIPM over the CAN data bus, both turn signal indicators will be flashed ON and OFF. The TIPM also sends the appropriate electronic messages to the cluster to control the flash rate of the right and left turn signal indicators, as well as to control the click rate of an electromechanical relay soldered onto the cluster electronic circuit board that emulates the sound emitted by a conventional hazard warning flasher. The turn signal indicators continue to flash ON and OFF until the cluster receives a hazard warning-OFF message from the TIPM.
- Turn Signal-On Textual Warning Message - When the cluster detects that a turn signal has been active continuously for 1.6 kilometers (1 mile) with the vehicle speed greater than 22 kilometers-per-hour (15 miles-per hour) a chime tone will be sounded and, if the vehicle is so equipped, a TURN SIGNAL ON textual message will appear within the instrument cluster reconfigurable Vacuum Fluorescent Display (VFD) unit.
- Lamp Out Mode - If the TIPM detects an ineffective turn signal lamp or circuit, it increases the flash rate for the remaining operative turn signals and sends an electronic message to the instrument cluster. To provide an indication of the problem to the vehicle operator the instrument cluster then increases the flash rate of the turn signal indicators, the click rate of the electromechanical relay and, if the vehicle is so equipped, displays a TURN SIGNAL LAMP OUT textual message in the reconfigurable VFD unit.

The CCN continually monitors the electronic messages from the TIPM to determine the proper turn signal and hazard warning indicator operation.