Part 2

OPERATION

ESP/BAS INDICATOR

The ESP/BAS indicator gives an indication to the vehicle operator when the Electronic Stability Program (ESP)/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 Controller Antilock Brake (CAB) and the All-Wheel Drive Control Module (AWDCM) over the Controller Area Network (CAN) data bus. Each time the ignition switch is turned to the ON position the ESP/BAS indicator is illuminated for about four seconds as a bulb test.

The ESP/BAS indicator Light Emitting Diode (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 ESP/BAS indicator for the following reasons:

- ESP/BAS Indicator Lamp-On Message - Each time the cluster receives an electronic ESP/BAS indicator lamp-ON message from the CAB indicating that the ESP/BAS system has been activated, the ESP/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.
- ESP Full Off Textual Message - Each time the cluster receives an electronic ESP Full OFF indicator lamp-ON message from the CAB indicating that the ESP/BAS system has been manually disabled, an ESP Full OFF textual message will appear within the cluster odometer display. The ESP Full 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.
- ESP Permanent Disable Textual Message - Each time the cluster receives an electronic ESP Permanent Disable message from the CAB indicating that the ESP/BAS system has been permanently disabled, an ESP OFF textual message will appear within the cluster odometer display for about 10 seconds each time the ignition switch is turned to the ON position.

The CAB continually monitors the ESP/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 then sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN).

ETC 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 Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus. Each time the ignition switch is turned to the ON position the ETC indicator is illuminated for about three seconds. The entire bulb test is a function of the instrument cluster.

The ETC indicator Light Emitting Diode (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.
- Actuator Test - Each time the cluster is put through the actuator test, the ETC indicator will be turned ON, then OFF again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry. The actuator test illumination of the ETC indicator is a function of the PCM.

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 ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/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 Diagnostic Trouble Code (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.

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 Controller Area Network (CAN) data bus.

The front fog lamp indicator Light Emitting Diode (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 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 request messages from the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN) to determine the appropriate outputs to the front fog lamps. The TIPM activates or deactivates the front fog lamps then sends the proper lamp-ON or lamp-OFF message back to the CCN.

FOUR-WHEEL DRIVE INDICATOR

The four-wheel drive indicator gives an indication to the vehicle operator when a four-wheel drive (4WD) mode of the transfer case is selected. This indicator is controlled either by the instrument cluster circuit board (domestic market vehicles) or by a transistor on the circuit board (export market vehicles) based upon cluster programming and electronic messages received by the cluster from the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus.

The four-wheel drive indicator 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 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 instrument cluster will turn ON the four-wheel drive indicator for the following reasons:

- Four-Wheel Drive Indicator Lamp-On Message - Each time the cluster receives an electronic four-wheel drive indicator lamp-ON message from the TIPM indicating that a four-wheel drive mode is selected, the four-wheel drive indicator is illuminated. The indicator remains illuminated 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.

The TIPM continually monitors inputs from the four-wheel drive switch to determine the status of the transfer case. The TIPM then sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN).

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 Controller Area Network (CAN) data bus from the Powertrain Control Module (PCM).

The gas cap indicator function of the odometer Vacuum Fluorescent Display (VFD) 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 odometer VFD 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 illuminated. 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 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 ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/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.

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 by the cluster from the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus.

The high beam indicator Light Emitting Diode (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 TIPM indicating the high beam lamps are turned ON, the high beam 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 request messages from the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN) to determine the appropriate outputs to the headlamps. The TIPM activates or deactivates the headlamp high beams then sends the proper lamp-ON or lamp-OFF message back to the CCN.

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 instrument cluster circuit board based upon cluster programming and electronic fuel level messages received by the cluster from the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus. Each time the ignition switch is turned to the ON position the low fuel indicator is illuminated for about three seconds as a bulb test.

The low fuel indicator Light Emitting Diode (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 low fuel indicator for the following reasons:

- Less Than 11 Percent Tank Full Message - The TIPM 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 TIPM 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 TIPM.
- 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 TIPM 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 TIPM is an open circuit.

The TIPM continually monitors the fuel tank sending unit to determine the level of fuel in the fuel tank. The TIPM then sends the proper electronic fuel level message to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN) and other electronic modules in the vehicle over the Controller Area Network (CAN) data bus. The TIPM 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 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 Controller Area Network (CAN) data bus.

The low oil pressure indicator Light Emitting Diode (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 low oil pressure indicator for the following reasons:

- Engine Oil Pressure Low Message - Each time the cluster receives an electronic engine oil pressure message from the PCM indicating the pressure is about 6.9 kPa (1 psi) or lower, the low oil pressure 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 flashing until the cluster receives a message from the PCM indicating that the pressure is above about 6.9 kPa (1 psi), or until the ignition switch is turned to the OFF position, whichever occurs first. The cluster will only turn the indicator ON in response to low engine oil pressure 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 messages to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN). If the CCN turns ON the indicator after the bulb test, it may indicate that the engine or the engine oiling system requires service.

LOW TIRE PRESSURE INDICATOR

The Tire Pressure Monitor (TPM) indicator gives an indication to the vehicle operator of the status of the TPM system. The TPM indicator is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Sentry Key Remote Entry Module (SKREEM) (also known as the Sentry Key Immobilizer Module/SKIM or the Wireless Control Module/WCM) over the Controller Area Network (CAN) data bus. Each time the ignition switch is turned to the ON position, the SKREEM sends an electronic TPM indicator lamp-ON message to the cluster to illuminate the TPM indicator for about three seconds as a bulb test.

The TPM indicator 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 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 instrument cluster will turn ON the TPM indicator for the following reasons:

- TPM Indicator Lamp-On Message - Each time the cluster receives an electronic TPM indicator lamp-ON message from the SKREEM, the 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 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.
- Low Tire Textual Message - On vehicles manufactured for export markets, each time the cluster receives an electronic TPM indicator lamp-ON message from the SKREEM requesting the TPM indicator be illuminated solid, a LOtIRE textual message will appear within the cluster odometer display. The LOtIRE textual message remains displayed 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.
- Communication Error - If the cluster receives no TPM lamp-ON or lamp-OFF messages from the SKREEM for six consecutive seconds, the TPM 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 SKREEM performs a self-test each time the ignition switch is turned to the ON position to decide whether the TPM system is in good operating condition and whether the tire inflation pressures are too high or too low. The SKREEM then sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN). If the instrument cluster turns ON the TPM indicator after the bulb test, it indicates that the inflation pressure of a tire is too low or that a malfunction has occurred and the TPM system is ineffective.

MALFUNCTION INDICATOR

The Malfunction Indicator Lamp (MIL) gives an indication to the vehicle operator when the Powertrain Control Module (PCM) has recorded a Diagnostic Trouble Code (DTC) for an On-Board Diagnostics II (OBDII) emissions-related circuit or component malfunction. The MIL is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM over the Controller Area Network (CAN) data bus. Each time the ignition switch is turned to the ON position the indicator is illuminated for about 15 seconds as a bulb test. The entire bulb test is a function of the PCM.

The MIL 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 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 instrument cluster will turn ON the MIL for the following reasons:

- MIL Lamp-On Message - Each time the cluster receives an electronic 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 PCM message. For some DTCs, if a problem does not recur, the PCM will send a lamp-OFF message automatically. Other DTCs may require that a fault be repaired and the PCM be reset before a lamp-OFF message will be sent. For more information on the PCM, and the DTC set and reset parameters.
- Communication Error - If the cluster receives no lamp-ON or lamp-OFF messages from the PCM for 10 consecutive message cycles, the MIL is illuminated by the instrument cluster 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.

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 sends the proper lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (CCN) (also known as the Cab Compartment Node/CCN). If the CCN turns ON the MIL after the bulb test, it may indicate that a malfunction has occurred and that the fuel and emissions systems require service.