Part 3

OPERATION

ESC OFF INDICATOR

The ESC OFF indicator gives an indication to the vehicle operator when the ESC System has been either permanently disabled or manually turned OFF. This indicator is controlled by the IPC circuit board based upon programming and electronic messages received from the CAB over the CAN data bus. The IPC will illuminate the traction control indicator for about four seconds each time the ignition is turned to the ON position, during the bulb test. The CAB communicates to the IPC over the CAN data bus, and the IPC then illuminates the indicator based on the lamp-on or lamp-off messages.
The ESC indicator is completely controlled by the instrument cluster logic circuit, and only allows 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 switched to ground by the instrument cluster circuitry. The instrument cluster will turn on the traction control indicator for the following reasons:
- ESC OFF Message - Each time the IPC 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 appear within the cluster. The ESC OFF indicator remains displayed until the IPC receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
- ESC Disable Message - Each time the IPC receives an electronic ESC Disable message from the CAB indicating that the ESC system has been permanently disabled, theESC OFF indicator will be illuminated within the IPC each time the ignition switch is turned to the ON position, and the ESC OFF switch has be depressed.

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 BCM, which in turn communicates these message to the IPC.

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

FOG LAMP INDICATOR

The fog lamp indicator gives an indication to the vehicle operator whenever the optional fog lamps are illuminated. This indicator is controlled by the IPC circuit board based upon programming and electronic messages from the BCM over the CAN data bus.

The fog lamp indicator LED is completely controlled by the IPC logic circuit, and will allow the 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 IPC transistor. The IPC will turn on the fog lamp indicator for the following reasons:

- Fog Lamp-ON Message - Each time the IPC receives a fog lamp-on message indicating the fog lamp relay is energized, the fog lamp indicator will be illuminated. The indicator remains illuminated until the cluster receives a fog lamp-off message.

The BCM continually monitors a hard-wired input from the headlamp switch to determine the selected fog lamp switch status. The BCM then sends the proper fog lamp-on and lamp-off messages to the IPC over the CAN data bus. The BCM activates the fog lamp relay then sends the proper fog lamp indicator lamp-on and lamp-off messages to the IPC.

FUEL SAVER INDICATOR - ECONOMIZER (ECO)

The ECO message will display in the IPC EVIC display. The message will appear whenever the vehicle is driven in a fuel efficient manner, if the feature is turned ON 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.

HIGH BEAM INDICATOR

The high beam indicator gives an indication to the vehicle operator whenever the headlamp high beams are illuminated. The BCM sends a data Bus message for high beam indicator illumination, in turn the IPC takes this data Bus message directive to turn on the indicator.

The high beam indicator LED is completely controlled by the IPC logic circuit, and will allow the indicator to operate whenever the IPC 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 IPC. The IPC will turn on the high beam indicator for the following reasons:

- High Beam Headlamps-ON Input - Each time the IPC detects a high beam headlamps-on input from the headlamp beam select switch circuitry of the multi-function switch on the washer/beam select switch mux circuit, the headlamp high beams and the high beam indicator will be illuminated. The headlamp high beams and the high beam indicator remain illuminated until the IPC receives a high beam headlamps-off input from the multi-function switch, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.

The BCM continually monitors the headlamp switch and the multi-function switch to determine the proper headlamp low beam and high beam control. The BCM then sends the proper low beam and high beam lamp-on and lamp-off messages to the IPC over the CAN data bus, and turns the high beam indicator on or off accordingly.

LOW FUEL INDICATOR

The low fuel indicator gives an indication to the vehicle operator when the level of fuel in the fuel tank becomes low. This indicator is controlled by a transistor on the IPC circuit board based upon programming and electronic fuel level messages received from the BCM over the CAN data bus. The IPC will illuminate the low fuel indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test

The low fuel indicator LED is completely controlled by the IPC logic circuit, and will only allow 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 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 IPC transistor. The IPC will illuminate the low fuel indicator for the following reasons:

- Less Than 11 Percent Tank Full Message - The BCM provides a constant current source to the fuel level sending unit and monitors a return input on a fuel level sense circuit. The resistance through the fuel level sending unit increases as the fuel level rises and decreases as the fuel level falls causing changes in the fuel level sense input voltage. The BCM then sends the appropriate electronic fuel level messages to the cluster. Each time the fuel level messages to the cluster indicate the fuel tank is about 11 percent full or less for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero, the gauge needle is moved to the appropriate position on the gauge scale, the low fuel indicator is illuminated, and a single chime tone is sounded. The low fuel indicator remains illuminated until the fuel level messages indicate that the fuel tank is greater than about 14 percent full for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero, 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 low fuel indicator is cycled OFF and then ON again by the appropriate messages from the BCM.
- Less Than Empty Stop Message - Each time the cluster receives a fuel level message indicating the fuel level in the fuel tank is less than the E (or Empty) gauge needle stop position for five consecutive seconds, the gauge needle is moved to the low end of the gauge scale and the low fuel indicator is illuminated immediately. This input would indicate that the fuel level sense input to the BCM is a short circuit.
- More Than Full Stop Message - Each time the cluster receives a fuel level message indicating the fuel level in the fuel tank is more than the F (or Full) gauge needle stop position for five consecutive seconds, the gauge needle is moved to the low end of the gauge scale and the low fuel indicator is illuminated immediately. This input would indicate that the fuel level sense input to the BCM is an open circuit.

The BCM continually monitors the fuel tank sending unit to determine the level of fuel in the fuel tank. The BCM then sends the proper electronic fuel level message to the IPC and other electronic modules in the vehicle over the CAN data bus. The BCM will store a Diagnostic Trouble Code (DTC) for any fault detected in the fuel level sense circuit.

LOW OIL PRESSURE INDICATOR

The low oil pressure indicator gives an indication to the vehicle operator when the engine oil pressure reading reflects a condition requiring immediate attention. This indicator is controlled by the IPC circuit board based upon programming and electronic messages received from the PCM over the CAN data bus.

The low oil pressure indicator LED is completely controlled by the instrument cluster logic circuit, and 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 IPC. The IPC will turn on the low oil pressure indicator for the following reasons:

- Engine Oil Pressure Low Message - Each time the IPC receives a message from the PCM indicating the engine oil pressure is about 4 psi (27.5 kPa) or lower, the low oil pressure indicator will be illuminated. The indicator remains illuminated until the IPC receives a message from the PCM indicating that the engine oil pressure is above about 4 psi (27.5 kPa), or until the ignition switch is turned to the OFF position, whichever occurs first. The IPC will only turn the indicator on in response to an engine oil pressure low message if the engine speed is greater than zero.

The PCM continually monitors the engine oil pressure sensor to determine the engine oil pressure. The PCM then sends the proper engine oil pressure messages to the IPC.

LOW TIRE PRESSURE INDICATOR

The low tire pressure indicator gives an indication to the vehicle operator of the status of the low tire pressure system. The low tire indicator is controlled by the IPC circuit board based upon programming and electronic messages received from the Tire Pressure Module (TPM) over the CAN data bus. The IPC will illuminate the TPM indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test

The TPM indicator is completely controlled by the IPC logic circuit, and will allow this indicator to operate when the IPC 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 energized by the instrument cluster logic circuit. The IPC will illuminate the TPM indicator for the following reasons:

- TPM Indicator Lamp-ON Message - Each time the IPC receives an electronic TPM indicator lamp-ON message from the TPM, the indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the TPM message. The indicator remains illuminated until the cluster receives a lamp-OFF message, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Low Tire Textual Message - ON vehicles manufactured for export markets, each time the IPC receives an electronic TPM indicator lamp-ON message from the TPM requesting the low tire pressure indicator be illuminated solid, and remains illuminated until the IPC receives a lamp-OFF message, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Communication Error - If the IPC receives no lamp-ON or lamp-OFF messages from the TPM for six consecutive seconds, the indicator is illuminated. The indicator remains controlled and illuminated by the IPC until a valid lamp-ON or lamp-OFF message is received from the TPM.

MALFUNCTION INDICATOR LAMP

The Malfunction Indicator Lamp (MIL) gives an indication to the vehicle operator when the PCM has recorded a DTC for an ON-Board Diagnostics II (OBDII) emissions-related circuit or component malfunction. The MIL is controlled by a transistor on the IPC circuit board based upon programming and electronic messages received over the CAN data bus. The IPC will illuminate the MIL indicator for about fifteen seconds each time the ignition is turned to the ON position, during the bulb test.

The MIL LED is completely controlled by the IPC 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 IPC transistor. The IPC will also turn on the MIL for the following reasons:

The PCM continually monitors the fuel and emissions system circuits and sensors to decide whether the system is in good operating condition. The PCM then communicates to the IPC over the CAN data bus. If the IPC 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.

- MIL Lamp-ON Message - Each time the IPC receives a MIL lamp-on message from the PCM, the indicator will be illuminated. The indicator can be flashed on and off, or illuminated solid, as dictated by the BCM message. For some DTC's, if a problem does not recur, the BCM will send a lamp-off message automatically. Other DTC's may require that a fault be repaired and the BCM be reset before a lamp-off message will be sent.
- Communication Error - If the IPC receives no messages from the BCM for ten consecutive message cycles, the MIL is illuminated by the IPC to indicate a loss of bus communication. The indicator remains illuminated until a valid message is received from the PCM.

SEAT BELT INDICATOR

The seat belt indicator gives an indication to the vehicle operator of the status of the driver side front seat belt. This indicator is controlled by the IPC circuit board based upon programming and a hard-wired 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 "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 seat belt indicator LED is completely controlled by the IPC logic circuit, and 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 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 IPC transistor. The IPC will turn on the seat belt indicator for the following reasons:

- Seat Belt Reminder Function - Each time the IPC receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator will be illuminated 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 IPC detects an open circuit on the seat belt indicator driver circuit (seat belt switch open = seat belt unbuckled) with the ignition switch in the START or ON positions, the indicator will be illuminated. 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 about5 MPH (8 Kph), the seat belt indicator will begin to cycle between flashing on and off for three seconds, then lighting solid for two seconds. The seat belt indicator will continue 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 START or ON positions, the indicator will be illuminated. 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.

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.

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 IPC electronic circuit board based upon the cluster programming, a hard-wired multiplex input received by the cluster from the turn signal and hazard warning switch circuitry of the multi-function switch on the turn/hazard switch mux circuit, and electronic messages received from the BCM over the CAN data bus.

Each turn signal indicator LED is completely controlled by the IPC logic circuit, and 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 IPC transistor. The IPC will turn on the turn signal indicators for the following reasons:

- Turn Signal-ON Input - The Steering Control Module (SCM) sends a Data Bus message to the BCM to turn on the turn signals. The BCM also sends out a message to the IPC to illuminate the appropriate electronic turn signal switch indicator. The BCM controls the output and the flash rate for either the right or left turn signal lamps and sends this message to the IPC. The IPC will then control 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 IPC 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 turn signal flashers are also controlled by the BCM. The SCM sends a Data Bus message to the BCM and the BCM responds to these messages by controlling a battery voltage output and the flash rate for each of the right and left turn signal lamps. The BCM also sends the appropriate electronic messages back to the IPC to control the illumination and 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 IPC 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 from the multi-function switch.
- Lamp Out Mode - The IPC also sends electronic turn signal on and off messages to the BCM over the CAN data bus, and the BCM flashes the appropriate exterior turn signal lamps. If the BCM 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.

The IPC continually monitors the multi-function switch and electronic messages from the BCM to determine the proper turn signal and hazard warning system control.

WAIT-TO-START INDICATOR

The wait-to-start indicator gives an indication to the vehicle operator when the engine temperature is too cool for efficient and reliable engine starting, and the engine block heater should be plugged in. This indicator is controlled by the IPC circuit board based upon programming and electronic messages received from the BCM over the CAN data bus. When the BCM receives a message from the PCM that the engine temperature is too low for efficient starting, the BCM then sends and electronic message to the IPC to turn on the "Wait to start" indicator, and a "Plug in block heater" message will be displayed in the EVIC.

The wait-to-start indicator LED is completely controlled by the IPC logic circuit, and only allows 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 IPC transistor. The IPC will illuminate the wait-to-start indicator for the following reasons:

- Wait-To-START Indicator Lamp-ON Message - Each time the IPC receives an electronic wait-to-start indicator lamp-ON message from the PCM indicating that the engine temperature is too cool for efficient and reliable engine starting, the wait-to-start indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the BCM, until the PCM detects that the engine is running, or until the ignition switch is turned to the OFF position, whichever occurs first.