Part 2

OPERATION

CHANGE OIL INDICATOR

The change oil indicator gives an indication to the vehicle operator when a duty-cycle algorithm contained within the software of the Powertrain Control Module (PCM) determines that a recommended oil change interval has been attained. This indicator is controlled by the IPC logic circuit based upon programming and electronic messages received from the PCM over the CAN data bus.

The change oil indicator function 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 VFD change oil indication will always be OFF when the ignition switch is in any position except ON or START. The IPC will illuminate the change oil indicator for the following reasons:

- Change Oil Indicator Lamp-ON Message - Each time the ignition switch is turned to the ON position and the IPC receives an electronic change oil indicator lamp-ON message from the PCM indicating that a duty-cycle based recommended oil change interval has been attained, the change oil indicator will be illuminated for about three seconds, until the trip odometer reset switch button is depressed, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Change Oil Indicator Reset Procedure - Once an engine oil change has been completed, the PCM duty cycle counters can be reset using the following procedure. Turn the ignition switch to the ON position, but DO NOT start the engine. Slowly depress and release the accelerator pedal fully three times within ten seconds. Turn the ignition switch to the OFF position. If the change oil indicator illuminates the next time the engine is started, repeat this procedure.

The PCM continually monitors numerous sensor inputs to determine the duty-cycles to which the engine is being subjected. A pre-programmed algorithm within the PCM then determines when to send the proper lamp-ON or lamp-OFF message to the IPC.

CHARGING INDICATOR

The charging indicator gives an indication to the vehicle operator when the electrical system voltage is too low or too high. This indicator is controlled by a transistor on the IPC circuit board based upon programming and electronic messages received PCM over the CAN data bus. The IPC will illuminate the charge indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test.

The charging 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 also turn on the charging indicator for the following reasons:

- Voltage Low Message - Each time the IPC receives a message from the PCM indicating the electrical system voltage is low (less than about 11.5 volts is a charge fail condition), the charging indicator will be illuminated. The indicator remains illuminated until a message from the PCM indicating the electrical system voltage is normal (greater than about 12.0 volts, but less than 16.0 volts) is received, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Voltage High Message - Each time the IPC receives a message from the PCM indicating the electrical system voltage is high (greater than about 16.0 volts), the charging indicator will be illuminated. The indicator remains illuminated until a message from the PCM indicating the electrical system voltage is normal (less than about 15.5 volts, but greater than 11.5 volts) is received, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM continually monitors the electrical system voltage to control the generator output. The PCM then sends the proper system voltage messages to the IPC. If the charging indicator is turned on due to a charge fail or voltage high condition, it may indicate that the charging system requires service.

CRUISE INDICATOR

The cruise indicator gives an indication to the vehicle operator when the speed control system is ON, regardless of whether the speed control is engaged. 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 cruise indicator 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 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 illuminate the cruise indicator for the following reasons:

- Cruise Indicator Lamp-ON Message - Each time the IPC 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 is turned to the OFF position, 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 IPC.

DOOR AJAR INDICATOR

The ajar indicators give an indication to the vehicle operator that one or more of the passenger compartment doors or the swing gate may be open or not completely latched. These indicators are controlled by the IPC logic circuit based upon programming and electronic ajar switch status messages from the BCM over the CAN data bus.

The ajar indicator function 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 B(+) circuit. Therefore, the ajar indications can occur regardless of the ignition switch position. The IPC will turn On the ajar indicator for the following reasons:

- Ajar Switch Message Input - Each time the IPC receives a door or liftgate ajar switch status message indicating that a door, the liftgate or any combination of these is open or not completely latched with the ignition switch in any position, the ajar indicator will be illuminated. If the cluster detects a vehicle speed input greater than zero (kilometers or miles-per-hour) while the ignition switch is in the ON or START positions, the ajar indicator will be accompanied by a single chime tone. When the ignition switch is in any position except ON or START, any and all ajar indications will time out after about five minutes.

The BCM continually monitors the door and liftgate ajar switches to determine the status of the doors and liftgate. The BCM then sends the proper ajar switch status messages to the IPC. The door and liftgate ajar switches and their circuits may be diagnosed using conventional diagnostic tools and methods. Refer to the appropriate wiring information.

ELECTRONIC THROTTLE CONTROL INDICATOR

The Electronic Throttle Control (ETC) indicator gives an indication to the vehicle operator when the ETC system is faulty or inoperative. The ETC indicator is controlled by the IPC circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The IPC will illuminate the ETC indicator for about fifteen seconds each time the ignition is turned to the ON position, during the bulb test.

The ETC 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 also turn on the ETC indicator for the following reasons:

- ETC Lamp-ON Message - Each time the IPC receives a 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 twelve seconds or until a lamp-off message from the PCM is received, 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 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 messages to the IPC. If the PCM sends a lamp-on message after the bulb test, it indicates that the PCM has detected an ETC system malfunction and/or that the ETC system is inoperative. The PCM will store a DTC for any malfunction it detects. Each time the ETC indicator fails to illuminate due to an open or short in the IPC ETC indicator circuit, the IPC sends a message notifying the PCM of the condition and the IPC and the PCM will each store a DTC.

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 the IPC circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The IPC will illuminate the engine temperature indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test.

The engine temperature 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 engine temperature indicator will also be turned on for the following reasons:

- Engine Temperature High Message - Each time the IPC receives a message from the PCM indicating the engine coolant temperature is above about 248° F (120° 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 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 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 IPC over the CAN data bus. If the IPC 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 STABILITY CONTROL (ESC) INDICATOR

The ESC indicator gives an indication to the vehicle operator when the ESC system has been activated. 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 BSM then communicates over the CAN data bus. The IPC will illuminate the ESC indicator for about four seconds each time the ignition is turned to the ON position, during the bulb test

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 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 is turned to the OFF position, whichever occurs first.
- Traction Control Lamp-ON Message - Each time the IPC receives a traction control lamp-ON message from the BCM indicating that the ESC has been activated, the traction control indicator will be illuminated. The indicator remains illuminated until a lamp-off message from the CAB is received, 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 ABS. The CAB then sends the proper traction control lamp-on, and lamp-OFF messages to the IPC.