Part 3

OPERATION - Continued

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 CCN circuit board based upon programming and electronic messages received from the PCM over the CAN data bus. The CCN 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 CCN 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 MIL for the following reasons:

- MIL Lamp-On Message - Each time the CCN 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 PCM message. For some DTC's, if a problem does not recur, the PCM will send a lamp-off message automatically. Other DTC's 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, Testing and Inspection.
- Communication Error - If the CCN receives no messages from the PCM for ten consecutive message cycles, the MIL is illuminated by the CCN to indicate a loss of bus communication. The indicator remains illuminated 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 messages 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 may require service.

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 a transistor on the CCN circuit board based upon cluster 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 CCN 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 turn on the seat belt indicator for the following reasons:

- Seat Belt Reminder Function - Each time the CCN 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 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. 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.

SECURITY INDICATOR

The security indicator gives an indication to the vehicle operator when the Vehicle Theft Security System (VTSS) is arming or is armed. On models equipped with the Sentry Key Immobilizer System (SKIS), the security indicator also gives an indication to the vehicle operator of the status of the SKIS. This indicator is controlled by a transistor on the CCN circuit board based upon programming, hard-wired inputs to the CCN from the various security system components, electronic messages received from the Wireless Ignition Node (WIN) over the CAN data bus. The CCN will illuminate the security indicator for about three seconds each time the ignition is turned to the ON position, during the bulb test.

The security indicator LED is completely controlled by the CCN 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 CCN transistor. The CCN will also turn on the security indicator for the following reasons:

- VTSS Indication - During the sixteen second VTSS arming function, the cluster will flash the security indicator on and off repeatedly at a steady, fast rate to indicate that the VTSS is in the process of arming. Following successful VTSS arming, the cluster flashes the security indicator on and off continuously at a slower rate to indicate that the VTSS is armed. The security indicator continues flashing at the slower rate until the VTSS is disarmed or triggered. If the VTSS has alarmed and rearmed, the cluster will flash the security indicator at a steady, slow rate for about thirty seconds after the VTSS is disarmed.
- SKIS Lamp-On Message - Each time the cluster receives a SKIS lamp-on message from the WIN, the security 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 solid or continues to flash until the cluster receives a SKIS lamp-off message from the WIN, or until the ignition switch is turned to the Off position, whichever occurs first. For more information on the SKIS and the security indicator control parameters, Wireless Ignition Node Receiver - Operation.
- Communication Error - If the CCN receives no SKIS lamp-on or lamp-off messages from the WIN for ten consecutive message cycles, the security indicator is illuminated by the instrument cluster. The indicator remains controlled and illuminated by the cluster until a valid SKIS lamp-on or lamp-off message is received from the WIN.

The CCN circuitry controls the security indicator whenever the ignition switch is in the Off position and the VTSS is arming, armed, or alarming. Whenever the ignition switch is in the On or Start positions, the WIN performs a self-test to decide whether the SKIS is in good operating condition and whether a valid key is present in the ignition lock cylinder. The WIN then sends the proper lamp-on or lamp-off messages to the instrument cluster. If the instrument cluster flashes the security indicator upon ignition On, or turns on the security indicator solid after the bulb test, it indicates that a SKIS malfunction has occurred or that the SKIS is inoperative.

TRACTION CONTROL INDICATOR

The traction control indicator gives an indication to the vehicle operator when the electronic Traction Control System (TCS) has been activated. This indicator is controlled by the CCN circuit board based upon programming and electronic messages received from the CAB over the CAN data bus. The CCN 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 traction control 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 switched to ground by the instrument cluster circuitry. The instrument cluster will turn on the traction control indicator for the following reasons:

- Traction Control Lamp-On Message - Each time the cluster receives a traction control lamp-on message from the CAB indicating that the TCS has been activated, the traction control indicator will be illuminated. The indicator remains illuminated until a traction control 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 instrument cluster.

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 CCN 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 TIPM over the CAN data bus.

Each turn signal indicator LED is completely controlled by the CCN 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, 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 CCN transistor. The CCN 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 TIPM to turn on the turn signals. The TIPM also sends out a message to the CCN to illuminate the appropriate electronic turn signal switch indicator. The TIPM controls the output and the flash rate for either the right or left turn signal lamps and sends this message to the CCN. The CCN 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 CCN 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 TIPM. The SCM sends a Data Bus message to the TIPM and the TIPM 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 TIPM also sends the appropriate electronic messages back to the CCN 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 CCN 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 CCN also sends electronic turn signal on and off messages to the TIPM over the CAN data bus, and the TIPM flashes the appropriate exterior turn signal lamps. If the TIPM 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 CCN continually monitors the multi-function switch and electronic messages from the TIPM to determine the proper turn signal and hazard warning system control.

TRANSMISSION RANGE INDICATOR

The electronic transmission range indicator gives an indication to the vehicle operator of the transmission gear that has been selected with the automatic transmission gear selector lever. 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 transmission range indicator information is displayed by a dedicated VFD unit soldered onto the CCN electronic circuit board, and the VFD will not display the transmission range indicator information after the ignition switch is turned to the Off position. The CCN circuitry operates the transmission range indicator VFD to provide the following features:

- Selected Gear Message - Each time the CCN receives a selected gear message from the PCM, a box will be illuminated around the appropriate character in the gear selector indicator VFD. The box will remain illuminated until the cluster receives a different selected gear message, or until the ignition switch is turned to the Off position, whichever occurs first.
- Communication Error - If the CCN fails to receive a selected gear message from the PCM within three seconds, the CCN circuitry will display all gear selector positions boxed (selected) until a valid selected gear message is received or until the ignition switch is turned to the Off position, whichever occurs first.

The PCM continually monitors a hard-wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper selected gear messages to the CCN.

The hard-wired indicator inputs may be diagnosed using conventional diagnostic tools and procedures. However, the CCN circuitry and electronic CAN or LIN data bus message controlled indicators are diagnosed using the self-diagnostic CCN Self Test. Testing and Inspection. Proper testing of the CAN or LIN data bus and the electronic data bus message inputs to the CCN that control each indicator requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.