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 (Instrument Panel Cluster), download the module configuration from the scan tool into the new IPC (Instrument Panel Cluster). to carry out the Programmable Module Installation (PMI). It is also necessary to carry out a parameter reset procedure whenever a new IPC (Instrument Panel Cluster) or PCM is installed. Programmable Module Installation (PMI) Passive Anti-Theft System (PATS) Passive Anti-Theft System (PATS) Parameter Reset
The IPC (Instrument Panel Cluster) utilizes a microprocessor to control the gauge, indicator, message center and warning chime functions. Data is sent to the IPC (Instrument Panel Cluster) 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 (Instrument Panel Cluster) 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 (Instrument Panel Cluster) Gateway Function
The IPC (Instrument Panel Cluster) acts as a gateway module by receiving information in one format and transmitting it to other modules using another format. For example, the IPC (Instrument Panel Cluster) receives the vehicle speed data from the PCM over the HS-CAN (High Speed Controller Area Network), converts the data into an MS-CAN (Medium Speed Controller Area Network) message and sends (gateways) the message to other network modules such as the Audio Control Module (ACM) and the SJB (Smart Junction Box). This enables network communication between modules that do not communicate using the same network (HS-CAN (High Speed Controller Area Network) or the MS-CAN (Medium Speed Controller Area Network)).
IPC (Instrument Panel Cluster) Network Messages
The IPC (Instrument Panel Cluster) uses input messages from other modules to control the gauges, informational indicators, message center 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 (Instrument Panel Cluster) 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 (Instrument Panel Cluster) and throughout the vehicle. Once a DTC is set in the IPC (Instrument Panel Cluster), 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 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 (Instrument Panel Cluster) Configuration
The IPC (Instrument Panel Cluster) contains items that are configurable. While some configurable items are customer preference items configured using the scan tool, most items are configured at the end of the line production and only available for configuration through the PMI (Programmable Module Installation) procedure.
IPC (Instrument Panel Cluster) Configuration Parameters
IPC (Instrument Panel Cluster) Prove-Out
The IPC (Instrument Panel Cluster) carries out a display prove-out to verify that all module controlled warning/indicator lamps and monitored systems are functioning correctly within the IPC (Instrument Panel Cluster). When the ignition is in the ON mode with the engine off, the indicators illuminate to prove-out according to the following table:
Information And Message Center
The message center is an integral part of the IPC (Instrument Panel Cluster) that receives and acts upon much of the same information that is input and used to operate the IPC (Instrument Panel Cluster) gauges, informational indicators, message center indicators, warning indicators and warning chimes. The message center is a 2-line display located in the center of the IPC (Instrument Panel Cluster). The message center functions use both hardwired circuitry, and the Controller Area Network (CAN) to display information.
Warning Chimes
The IPC (Instrument Panel Cluster) uses inputs that are both hardwired to individual components and messages that are sent from the other modules over the HS-CAN (High Speed Controller Area Network) or the MS-CAN (Medium Speed Controller Area Network) to control the warning chime functions.
Warning Chime Characteristics
Each warning chime has unique characteristics to identify and differentiate an individual 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 (Instrument Panel Cluster) prioritizes the chimes according to a preset hierarchy programmed into the IPC (Instrument Panel Cluster) software. When more than one chime request is received by the IPC (Instrument Panel Cluster), 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 (Instrument Panel Cluster) monitors the air bag warning indicator status internally. When a fault is present in the air bag warning indicator and the IPC (Instrument Panel Cluster) 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 inputs are:
- Ignition RUN/START status.
- Air bag warning indicator chime request communicated by the RCM (Restraints Control Module) to the IPC (Instrument Panel Cluster).
Belt-Minder(R)
The Belt-Minder(R) is configurable. To configure with a scan tool, refer to Information Bus. To configure without using a scan tool, refer to Belt-Minder(R) Deactivating/Activating Testing and Inspection.
The Belt-Minder(R) feature supplements the current safety belt warning function and is enabled after the current safety belt warning is complete (70 seconds). The Belt-Minder(R) reminds the driver that the driver safety belt is unbuckled by intermittently sounding a chime and alternately illuminating the safety belt warning lamp in the IPC (Instrument Panel Cluster) once the vehicle speed has exceeded 10 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 and indicator flash and chime alternately from on for 6 seconds to off for 30 seconds.
If the vehicle speed drops below 5 km/h (3 mph), the Belt-Minder(R) chime completes the current 6-second sequence then stops sounding. During this time of suspension, the safety belt warning indicator remains illuminated. Once the vehicle speed exceeds 10 km/h (6 mph), the chime begins again, restoring the Belt-Minder(R) to full function.
The Belt-Minder(R) warning chime inputs are the:
- Ignition RUN/START status.
- Driver safety belt warning chime request communicated by the RCM (Restraints Control Module) to the IPC (Instrument Panel Cluster) through the HS-CAN (High Speed Controller Area Network).
Headlamps On Warning Chime
The headlamps on warning chime warns that the headlamps 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 with the ignition in the OFF mode and 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 off mode to the SJB (Smart Junction Box).
- Door ajar input from the driver door ajar switch to the SJB (Smart Junction Box).
- Headlamp switch input to the SJB (Smart Junction Box).
- Headlamps on chime request communicated by the SJB (Smart Junction Box) to the IPC (Instrument Panel Cluster) through the MS-CAN (Medium Speed Controller Area Network).
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/LOCK 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 RUN position.
The key-in-ignition warning chime inputs are:
- Ignition status.
- Key-in-ignition switch position to the SJB (Smart Junction Box).
- Door ajar input from the driver door ajar switch to the SJB (Smart Junction Box).
- Key-in-ignition chime request communicated by the SJB (Smart Junction Box) to the IPC (Instrument Panel Cluster) through the MS-CAN (Medium Speed Controller Area Network).
Message Center Warning Chime
The message center warning chime feature is to draw the driver's attention to the message center display to view each new warning message. The IPC (Instrument Panel Cluster) 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 (Instrument Panel Cluster) sounds a chime for each of the warning messages that are present.
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 status.
- Parking brake switch input to the SJB (Smart Junction Box).
- Vehicle speed data communicated by the PCM to the IPC (Instrument Panel Cluster) through the HS-CAN (High Speed Controller Area Network) then gatewayed to the SJB (Smart Junction Box) through the MS-CAN (Medium Speed Controller Area Network).
- Parking brake warning chime request communicated by the SJB (Smart Junction Box) through the MS-CAN (Medium Speed Controller Area Network) to the IPC (Instrument Panel Cluster).
Safety Belt Warning Chime
The safety belt warning chime warns that the safety belt is not fastened. The safety belt warning chime sounds when the driver safety belt is not fastened and the ignition is changed from the OFF or ACC to the RUN or START mode.
The safety belt warning chime stops sounding when the safety belt is fastened, when the ignition is switched from the RUN or START mode to the OFF or ACC mode, or when the chime has sounded for approximately 6 seconds.
The safety belt warning chime inputs are:
- Ignition RUN/START status.
- Driver safety belt warning chime request communicated by the RCM (Restraints Control Module) to the IPC (Instrument Panel Cluster) through the HS-CAN (High Speed Controller Area Network).
Service Roll Stability Control (RSC(R)) Warning Chime
The service RSC(R) (Roll Stability Control) warning chime warns that the ABS module detects a fault condition in the RSC(R) (Roll Stability Control) system. The SERVICE RSC message is also displayed along with the chime.
The service RSC(R) (Roll Stability Control) chime sounds for 30 seconds and then stops sounding for 5 minutes then repeats the sequence. The RSC(R) (Roll Stability Control) chime stops sounding when the ignition lock cylinder is turned from the RUN/START position to the OFF/LOCK or ACC position or when the fault condition is repaired.
The service RSC(R) (Roll Stability Control) warning chime inputs are:
- Ignition switch RUN/START status.
- Service RSC(R) (Roll Stability Control) chime request communicated by the ABS module to the IPC (Instrument Panel Cluster) through the HS-CAN (High Speed Controller Area Network).
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 mode.
The turn signal left on warning chime inputs are:
- Ignition switch mode to the IPC (Instrument Panel Cluster) and SJB (Smart Junction Box).
- Turn signal on data communicated by the SJB (Smart Junction Box) to the IPC (Instrument Panel Cluster) through the CAN (Controller Area Network) communication.
- Odometer count data communicated by the PCM to the IPC (Instrument Panel Cluster) through the HS-CAN (High Speed Controller Area Network).
Turn/Hazard On Tone
Since the turn/hazard flasher is an electronic function of the SJB (Smart Junction Box), 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 (Instrument Panel Cluster) 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 (Smart Junction Box) to the IPC (Instrument Panel Cluster) through the MS-CAN (Medium Speed Controller Area Network).
- Right turn indicator signal from the SJB (Smart Junction Box) to the IPC (Instrument Panel Cluster) through the MS-CAN (Medium Speed Controller Area Network).