Part 3

OPERATION - LHD (Continued)

ESC OFF INDICATOR

The Electronic Stability Control (ESC) OFF indicator gives an indication to the vehicle operator that the ESP system has been manually disabled. 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 Transmission Control Module (TCM) over the CAN data bus.

The ESC OFF indicator function of the odometer 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 VFD ESC OFF indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the ESC OFF indicator for the following reasons:

- 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 ESP system has been manually disabled by depressing the ESC OFF switch button in the instrument panel switch pod, 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 is turned to the OFF position, whichever occurs first.

The CCN continually monitors the status of the ESC OFF switch over a LIN data bus circuit to determine the requested operating mode for the ESC system. The CCN then sends an electronic ESC OFF switch status message to the CAB over the CAN data bus. The CAB then sends the proper lamp-ON or lamp-OFF message back to the CCN, confirming the current operating mode of the ESC system.

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 instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the PCM/ECM over the CAN data bus.

The engine temperature 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. Each time the ignition switch is turned to the ON position the engine temperature indicator is illuminated for about two seconds as a bulb test. The entire bulb test is a function of the PCM/ECM. The instrument cluster will turn ON the engine temperature indicator for the following reasons:

- Engine Temperature High or Critical Message - Each time the cluster receives an electronic engine temperature message from the PCM/ECM indicating the temperature is high [at or above about 127 °C (261 °F) for gasoline engines, or about 128 °C (262 °F) for diesel engines], the engine temperature indicator will be illuminated and a single chime tone is sounded. The indicator remains illuminated until the cluster receives a message from the PCM/ECM indicating that the temperature is below about 124 °C (255 °F), 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, then ON again by the appropriate messages from the PCM/ECM.

The PCM/ECM continually monitors the engine coolant temperature sensor to determine the engine operating temperature. The PCM/ECM then sends the proper messages to the CCN. For further diagnosis of the engine temperature indicator or the instrument cluster circuitry that controls the LED Testing and Inspection. If the instrument cluster 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.

ELECTRONIC THROTTLE CONTROL (ETC) INDICATOR

The ETC indicator gives an indication to the vehicle operator when the ETC system, or a circuit or component of the system is inoperative. 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/ECM over the CAN data bus.

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. Each time the ignition switch is turned to the ON position the ETC indicator is illuminated for about three seconds, but no longer than 15 seconds. The entire bulb test is a function of the instrument cluster. 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/ECM, the ETC indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the PCM/ECM 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/ECM, 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/ECM continually monitors the ETC system circuits and sensors to decide whether the system is in good operating condition. The PCM/ECM then sends the proper lamp-ON or lamp-OFF message to the CCN. If the PCM/ECM sends a lamp-ON message after the bulb test, it indicates that the PCM/ECM has detected an ETC system malfunction or that the ETC system is ineffective. The PCM/ECM will store a DTC for any malfunction it detects.

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 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 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 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.

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.

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/ECM.

The gas cap indicator function of the odometer 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/ECM 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/ECM, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM/ECM continually monitors the on board vapor recovery system to determine whether there are air leaks in the system. The PCM/ECM 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.

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 TIPM 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 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 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 TIPM over the CAN data bus.

The low fuel 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. 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 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 ten 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 CCN and other electronic modules in the vehicle over the CAN data bus. The TIPM will store a 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 PCM/ECM over the CAN data bus.

The low oil pressure 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 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/ECM 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/ECM message. The indicator remains illuminated solid or flashing until the cluster receives a message from the PCM/ECM 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/ECM continually monitors the engine oil pressure sensor to determine the engine oil pressure. The PCM/ECM then sends the proper messages to the 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

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 a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Wireless Ignition Node (WIN), over the CAN data bus.

The TPM 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. Each time the ignition switch is turned to the ON position, the WIN 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 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 WIN, the indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the WIN message. The indicator remains illuminated until the cluster receives a lamp-OFF message from the WIN, 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 WIN 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 WIN.

The WIN 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 WIN then sends the proper lamp-ON or lamp-OFF message to the 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 inoperative.

MALFUNCTION INDICATOR

The Malfunction Indicator Lamp (MIL) gives an indication to the vehicle operator when the PCM/ECM has recorded a 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/ECM over the CAN data bus.

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. 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/ECM. 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/ECM, the indicator will be illuminated. The indicator can be flashed ON and OFF, or illuminated solid, as dictated by the PCM/ECM message. For some DTCs, if a problem does not recur, the PCM/ECM will send a lamp-OFF message automatically. Other DTCs may require that a fault be repaired and the PCM/ECM be reset before a lamp-OFF message will be sent.
- Communication Error - If the cluster receives no lamp-ON or lamp-OFF messages from the PCM/ECM 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/ECM.

The PCM/ECM continually monitors the fuel and emissions system circuits and sensors to decide whether the system is in good operating condition. The PCM/ECM then sends the proper lamp-ON or lamp-OFF message to the 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.