Principles of Operation
Instrumentation, Message Center and Warning Chimes
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE: When installing a new Instrument Panel Cluster (IPC), it is necessary to upload the module configuration to the scan tool. Following installation of the IPC, download the module configuration from the scan tool into the new IPC. Refer to Information Bus to carry out the Programmable Module Installation (PMI). It is also necessary to carry out a parameter reset procedure whenever a new IPC or PCM (non-hybrid) or Transmission Control Module (TCM) (hybrid) is installed. Refer to Antitheft and Alarm Systems. Programming and Relearning
The IPC utilizes a microprocessor to control the gauge, indicator, message center and warning chime functions. Data is sent to the IPC over the Medium Speed Controller Area Network (MS-CAN) and the High Speed Controller Area Network (HS-CAN) bus lines and through hardwired circuitry from individual components. The IPC uses each input to output an action to the gauges or indicators.
It is very important to understand:
- where the input originates.
- all the information necessary in order for a feature to operate.
- which module(s) receive(s) the input or command message.
- does the module which received the input control the output of the feature, or does it output a message over the communication network to another module.
- which module controls the output of the feature.
Instrument Panel Cluster (IPC)
IPC Gateway Function
The IPC acts as a gateway module by receiving information in one format and transmitting it to other modules using another format. For example, the IPC receives the vehicle speed data from the PCM over the HS-CAN, converts the data into an MS-CAN message and sends (gateways) the message to other network modules such as the HVAC module, the Audio Control Module (ACM) and the SJB. This enables network communication between modules that do not communicate using the same network (HS-CAN or the MS-CAN).
IPC Network Messages
The IPC uses input messages from other modules to control the gauges, informational indicators and warning indicators over the communication networks. If a required message is missing or invalid for less than 5 seconds, the gauge or indicator that requires the message remains at the last commanded state based upon the last known good message. For example, if the brake status message is missing for less than 5 seconds and the brake warning indicator was on, the indicator remains in the on state until the next good message is received. If the message remains missing or invalid for greater than 5 seconds, the IPC sets a U-code DTC and the output becomes a default action for the indicator or gauge. Each indicator or gauge utilizes a different default strategy depending on the nature of the indication. Refer to the normal operation descriptions located before each individual pinpoint test for further description of the default action specific to each indicator or gauge. If the messaged input to the cluster returns at any time, the normal function of the gauge or indicator resumes.
NOTE: Whenever a network message is suspected as missing and confirmed by a missing message DTC (U-code), it is important to look for other symptoms that may also be present in the IPC and throughout the vehicle. Once a DTC is set in the IPC, it may be helpful to review the complete message list available in Information Bus to see what other modules also rely on the same message and run the self-test for those modules. If the message is missing from other modules, the same DTC may also be set in those modules. Confirmation of missing messages common to multiple modules may indicate that the originating module is the source of the concern or the communication network may be experiencing some problems.
IPC Configuration
The IPC contains items that are configurable. Configurable items include customer preference items, which can also be set with a scan tool. The remaining configurable items can be set only through the PMI procedure or by using As-Built data. Refer to Information Bus.
IPC Configuration Parameters
IPC Configuration Parameters - Hybrid
IPC Software Flashing
The IPC is capable of receiving updated software after the end of line production. This software updating is called software flashing and is only carried out when a Technical Service Bulletin (TSB) provides the direction to do so. Follow all instructions on the TSB when flashing the IPC.
IPC Prove-Out
The IPC carries out a display prove-out to verify that all module controlled warning/indicator lamps and monitored systems are functioning correctly within the IPC. When the ignition is in the ON mode with the engine off, the indicators illuminate to prove-out according to the following table:
Non-Hybrid
Hybrid
Information And Message Center
The message center is an integral part of the IPC that receives and acts upon much of the same information that is input and used to operate the IPC gauges, informational indicators, warning indicators and warning chimes. For all vehicles except hybrid, the message center is a 2-line display located in the center of the IPC. On hybrid vehicles, the message center is split between the LH and RH side of the IPC with the controls displayed on the LH side and instructions displayed on the RH side. The hybrid message center also uses message center indicators either as stand alone indications or combined with text messages and are displayed in the LH display area.
All message center functions are controlled by a 3-button message center switch, which is hardwired to the IPC. The message center switch consists of 3 buttons and a resistor ladder with a different resistor associated with each switch button. The IPC sends out a reference voltage to the message center switch and monitors the voltage drop that results from the voltage flowing through the resistor when a message center button is pressed. The voltage drop will vary depending upon the resistance of each button, providing a specific indication to the IPC which switch is pressed.
Warning Chimes
The IPC uses inputs that are hardwired to individual components and messages that are sent from the other modules over the HS-CAN or MS-CAN to control the warning chime functions.
Warning Chime Characteristics
Each warning chime has unique characteristics to identify and differentiate each warning chime. The warning chimes use volume, chime frequency, length of time the chime sounds and the number of chime tones to identify which chime is sounding. The IPC prioritizes the chimes according to a preset hierarchy programmed into the IPC software. When more than one chime request is received by the IPC, the most important chime sounds. If a lower priority chime is currently sounding, the higher priority request takes over and replaces the lower priority chime.
There are 3 different chimes as listed below:
- Repetitive
- Single tone
- Tick-tock
The following table provides a summary of the chime characteristics.
Instrument Panel Cluster (IPC) Chime Characteristics
Air Bag Secondary Warning Chime
The air bag secondary warning chime warns that the air bag warning indicator light does not work correctly and that a Supplemental Restraint System (SRS) fault condition exists. The IPC monitors the air bag warning indicator status internally. When a fault is present in the air bag warning indicator and the IPC receives an air bag warning indicator on request from the Restraints Control Module (RCM), the air bag secondary warning chime sounds.
The air bag secondary warning chime sounds for 1 second on then 1 second off for 5 seconds (5 1-second chime tones) then pauses for 5 seconds and repeats the chime on/off sequence for 5 minutes. The IPC then turns off the air bag chime for approximately 30 minutes and repeats the cycle if the condition still exists.
The air bag secondary warning chime inputs are:
- Ignition state.
- Air bag warning indicator chime request communicated by the RCM to the IPC.
Belt-Minder(R)
The Belt-Minder(R) is configurable. To configure without using a scan tool, refer to Belt-Minder(R) Deactivating/Activating Service and Repair.
The Belt-Minder(R) feature supplements the current safety belt warning function and is enabled after the current safety belt warning is complete. The Belt-Minder(R) reminds the driver that the driver or passenger safety belt is unbuckled by intermittently and simultaneously sounding a chime and illuminating the safety belt warning indicator in the IPC once the vehicle speed has exceeded 9.7 km/h (6 mph). The Belt-Minder(R) remains active for 5 minutes from the time it is started.
While activated, the Belt-Minder(R) chime provides a series of 6 chime/safety belt warning indicator flash sequences that when combined, make up a chime cycle. Each chime/safety belt warning indicator sequence consists of a 1-second chime tone and safety belt warning indicator on/off state. The Belt-Minder(R) chime and the safety belt warning indicator sound and flash for 6 seconds, then the chime stops and the safety belt warning indicator remains on for 30 seconds. The IPC repeats the chime cycle for 5 minutes.
If the vehicle speed drops below 5 km/h (3 mph) once the Belt-Minder(R) chime has activated, the chime turns off and the safety belt warning indicator remains on. When the vehicle speed exceeds 9.7 km/h (6 mph) again, the Belt-Minder(R) chime resumes.
The IPC also provides a toll booth feature which allows the driver or passenger to unbuckle their safety belt after the safety belts were initially buckled, providing 1 minute without warnings after the vehicle exceeds 9.7 km/h (6 mph) again with a safety belt unbuckled.
The Belt-Minder(R) warning chime inputs are the:
- Ignition state.
- Driver or passenger safety belt warning chime request communicated by the RCM to the IPC through the HS-CAN.
- Safety belt warning indicator request communicated by the RCM to the IPC through the HS-CAN.
Door Ajar Warning Chime
The door ajar warning chime warns that a door is ajar. The door ajar warning chime is a single chime with a 1 second duration. The door ajar chime sounds when the driver or passenger doors become ajar while the ignition switch is in the RUN position.
The door ajar warning chime inputs are the:
- Ignition state.
- Door ajar, liftgate or liftgate glass message from the SJB.
Headlamps On Warning Chime
The headlamps on warning chime warns that the headlamps or parking lamps are on when the driver door is ajar and the key is removed from the ignition lock cylinder. The headlamps on warning chime sounds if the driver door is ajar and the headlamp switch is in the PARK or HEADLAMP position and the ignition is OFF with the key out.
The headlamps on warning chime stops sounding when any one of the above conditions are removed.
The headlamps on warning chime inputs are:
- Ignition state.
- Key-in-ignition status to the SJB.
- Door ajar input from the driver door ajar switch to the SJB.
- Headlamp switch input to the SJB.
- Headlamps on chime request communicated by the SJB to the IPC through the MS-CAN.
Hybrid Electric Vehicle (HEV) Engine Off Chime
The HEV engine off chime sounds to remind the driver that the engine is not running and the vehicle is ready to drive. The HEV warning chime sounds when the key is in RUN, the driver door is ajar and the transaxle is in PARK (P).
The HEV warning chime inputs are:
- Ignition state.
- Door ajar input from the driver door ajar switch to the SJB.
- Door ajar status communicated from the SJB to the IPC through the MS-CAN.
- Transaxle park status communicated by the PCM to the IPC through the HS-CAN.
Key-In-Ignition Warning Chime
The key-in-ignition warning chime warns that the key is still in the ignition lock cylinder when the driver door is ajar. The key-in-ignition warning chime sounds when the driver door is ajar, the key is in the ignition lock cylinder and in the OFF or ACC position.
The key-in-ignition warning chime stops sounding when the driver door is closed, the key is removed from the ignition lock cylinder, or if the ignition switch is turned to the ON position.
The key-in-ignition warning chime inputs are:
- Ignition state.
- Key-in-ignition switch position to the SJB.
- Door ajar input from the driver door ajar switch to the SJB.
- Key-in-ignition chime request communicated by the SJB to the IPC through the MS-CAN.
Message Center Warning Chime
The message center warning chime feature is used to draw the driver's attention to the message center display to view a new warning message or message center warning indicator displayed. The IPC provides a single one-second tone whenever a new warning message is displayed in the message center. If multiple warning messages are present, the IPC sounds a chime for each of the warning messages that are present.
Memory Feedback Feature Chime
The purpose of the memory feedback feature chime is to inform the driver that their preferences have been successfully programmed through the memory set procedure.
The memory feature chime inputs are:
- Ignition RUN/START status.
- Memory feedback chime request communicated by the Driver Seat Module (DSM) to the IPC over the MS-CAN.
Parking Brake Warning Chime
The parking brake warning chime warns that the parking brake is engaged when the vehicle is in motion. The parking brake warning chime sounds if the ignition is in RUN mode, the parking brake is engaged, and the vehicle speed is greater than 5 km/h (3 mph).
The parking brake warning chime stops sounding if the parking brake is released, the ignition is not in the RUN mode, if the vehicle speed is less than 5 km/h (3 mph), or after 90 seconds from the time the chime is activated.
The parking brake warning chime inputs are:
- Ignition state.
- Parking brake switch status communicated by the SJB to the IPC through the MS-CAN.
- Vehicle speed data communicated by the PCM to the SJB through the MS-CAN.
- Parking brake warning chime request communicated by the SJB to the IPC.
Perimeter Alarm Chime
The perimeter alarm chime warning is used to alert the driver that the perimeter alarm is armed when the driver door is unlocked with a key. The perimeter alarm warning chime is only functional when a key is used to unlock the driver door. If the key fob or keypad (if equipped) is used to unlock the door, the perimeter alarm is disarmed and the perimeter alarm warning chime does not sound. The perimeter alarm warning chime sounds for 12 seconds when the driver door is opened and turns off when the perimeter alarm is disarmed (either by using the key fob, keypad or turning the key to the ON position). After the 12 second chime duration, the chime stops sounding and the perimeter alarm activates, sounding the horn and flashing the turn signal lights.
The perimeter alarm chime inputs are:
- Ignition state.
- Passive Anti-Theft System (PATS) armed/disarmed status.
- Driver door ajar input to the SJB.
- Perimeter alarm chime request from the SJB to the IPC through the MS-CAN.
Safety Belt Warning Chime
The safety belt warning chime warns that the safety belt is not fastened. The safety belt warning chime sounds for 6 seconds when the driver safety belt is not fastened and the ignition switch is transitioned from the OFF or ACC position to the ON or START position.
The safety belt warning chime stops sounding when the safety belt is fastened, when the ignition is switched from the ON or START position to the OFF or ACC position, or when the chime has sounded for approximately 6 seconds.
The safety belt warning chime inputs are:
- Ignition state.
- Driver or passenger safety belt warning chime request communicated by the RCM to the IPC through the HS-CAN.
Service Roll Stability Control (RSC(R)) Warning Chime
The service RSC(R) warning chime warns that the ABS module has detected a fault condition in the RSC(R) system. The SERVICE ADVANCETRAC message is also displayed along with the chime.
The service RSC(R) chime sounds for approximately 3 seconds following an initial delay of 8 seconds following key ON. The RSC(R) chime stops sounding when the ignition switch is turned from the RUN/START position to the OFF/LOCK or ACC position or when fault condition is repaired.
The service RSC(R) warning chime inputs are:
- Ignition state.
- Service RSC(R) chime request communicated by the ABS module to the IPC through the HS-CAN.
Turn Signal Left On Warning Chime
The turn signal left on warning chime warns that the turn signal has not been cancelled. The turn signal left on warning chime sounds if the left or right turn signal is on and the vehicle has traveled more than 3.2 km (2.0 miles).
The turn signal left on warning chime stops sounding if the turn signal is turned off, or if the ignition is switched to the OFF or ACC position.
The turn signal left on warning chime inputs are:
- Ignition state.
- Turn signal on data communicated by the SJB to the IPC through the MS-CAN.
- Odometer rolling count data communicated by the PCM to the IPC through the HS-CAN.
Turn/Hazard On Tone
Since the turn/hazard flasher is an electronic function of the SJB, the on/off sound that used to be present with standard bi-metal flashers is no longer present. To provide an audible sound and indicate that the RH/LH turn or hazard indicators are on, the IPC provides a tick-tock tone along with the visual turn signal indicators.
The turn/hazard on tone inputs are:
- Left turn indicator signal from the SJB to the IPC through the MS-CAN.
- Right turn indicator signal from the SJB to the IPC through the MS-CAN.