Part 2

OPERATION - Continued

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 instrument cluster logic circuit based upon programming and electronic messages received from the PCM over the CAN data bus.

The change oil indicator function of the VFD 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 change oil indication will always be OFF when the ignition switch is in any position except ON or START. The CCN 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 CCN 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 CCN.

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 CCN circuit board based upon programming and electronic messages received PCM over the CAN data bus. The CCN 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 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 CCN transistor. The CCN will also turn on the charging indicator for the following reasons:

- Voltage Low Message - Each time the CCN 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 CCN 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 CCN. 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 CCN 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 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 logic circuit. The instrument cluster will illuminate the cruise indicator for the following reasons:

- Cruise Indicator Lamp-ON Message - Each time the CCN 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 CCN.

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 instrument cluster logic circuit based upon programming and electronic ajar switch status messages from the TIPM over the CAN data bus.

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

- Ajar Switch Message Input - Each time the CCN receives a door or swing gate ajar switch status message indicating that a door, the swing gate or any combination of these is open or not completely latched with the ignition switch in any position, the appropriate ajar textual message 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 indication 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 TIPM continually monitors the door and swing gate ajar switches to determine the status of the doors and swing gate. The TIPM then sends the proper ajar switch status messages to the CCN. The door and swing gate 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 a transistor on the CCN circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The CCN 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 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 CCN transistor. The CCN will also turn on the ETC indicator for the following reasons:

- ETC Lamp-ON Message - Each time the CCN 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 CCN. 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 CCN ETC indicator circuit, the CCN sends a message notifying the PCM of the condition and the CCN 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 a transistor on the CCN circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The CCN 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 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 CCN transistor. The engine temperature indicator will also be turned on for the following reasons:

- Engine Temperature High Message - Each time the CCN receives a message from the PCM indicating the engine coolant temperature is above about 252° F (122° 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 CCN. If the CCN 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.