Principles of Operation
Instrumentation, Message Center and Warning Chimes
Principles of Operation
The Instrument Cluster (IC) is a configurable, hybrid electronic cluster that contains a microprocessor, gauges, indicators, message center, warning chimes and internal circuitry. The IC uses hardwired circuitry, the Standard Corporate Protocol (SCP), and the Controller Area Network (CAN) to transmit and receive data from other modules.
When installing a new IC, it is necessary to upload the module configuration information to the scan tool. Following installation of the IC, download the module configuration information from the scan tool into the new IC. Refer to Information Bus to carry out Programmable Module Installation (PMI). Programming and Relearning
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.
- whether the module which received the input controls the output of the feature, or whether it outputs a message over the SCP or the CAN circuits to another module.
- which module controls the output of the feature.
Instrument Cluster (IC)
IC Configuration
The IC 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 by the Programmable Module Installation (PMI) process or by using As-Built data. Refer to Information Bus.
IPC Configuration Parameters
IC Network Messages
The IC 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 for an indicator that requires the message, the indicator remains at the last commanded state based upon the last known good message.
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 can also be present in the IC and throughout the vehicle. Once a DTC is set in the IC, it can 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 can indicate that the originating module is the source of the concern or the communication network may be experiencing some problems.
IC Prove-Out
The IC and other vehicle modules carry out a display prove-out to verify that all module controlled warning/indicator lamps and monitored systems are operating correctly. When the ignition switch is turned to the ON position 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 IC that receives and acts upon much of the same information that is input and used to operate the IC gauges, informational indicators, and warning indicators. The message center electronic functions use both hardwired, and the CAN circuitry to transmit and receive information.
Whenever conditions are present that require a warning message, the message center replaces the last selected display with the new warning display. Once the message is reset or cleared, the message center returns to the last selected display. If multiple warnings are present, the message center displays each warning for approximately 4 seconds. Warning messages are also generally associated with other observable IC indications. For example, when the LH front door is opened, the message center displays the message DRIVER DOOR AJAR along with the door ajar warning indicator. This allows the message center to be a more informative supplement to the IC gauges and indicators.
Warning Chimes
The IC uses different chimes to alert the driver of various vehicle conditions as follows:
- Safety belt warning (repetitive chime)
- Belt-Minder(R) warning (repetitive chime after a delay and after the safety belt chime is completed)
- Key-in-ignition warning (repetitive chime)
- Turn signal on warning (repetitive chime)
- Headlamps on warning (repetitive chime)
- Air bag warning (repetitive chime)
- Message center warning (single tone)
- Fail safe cooling warning (repetitive chime)
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 key is turned from the OFF/LOCK or ACC to the ON or START position.
The chime stops sounding when the safety belt is fastened, when the ignition key is turned from the ON or START position to the OFF/LOCK or ACC position, or when the chime has sounded for approximately 6 seconds.
The safety belt warning chime inputs are the:
- Ignition switch RUN/START position
- Driver safety belt switch status signal from the Restraints Control Module (RCM)
Belt-Minder(R)
The Belt-Minder(R) feature supplements the current safety belt warning function. The Belt-Minder(R) 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 sounding a chime and illuminating the safety belt warning lamp in the IC once the vehicle speed has exceeded 5 km/h (3 mph). While activated, the Belt-Minder(R) alternates the chime and indicator from on for 6 seconds to off for 30 seconds.
NOTE: The Belt-Minder(R) is disabled for one ignition switch ON cycle if the safety belt is buckled then unbuckled quickly (within 20 seconds) during that specific cycle.
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 chime stops sounding when the driver door is closed, the key is removed from the ignition lock cylinder, or if the ignition key is turned to the ON position.
The key-in-ignition warning chime inputs are the:
- Ignition switch RUN/START position
- Door ajar signal from the driver door ajar switch
- Key-in-ignition switch signal from the ignition switch
Turn Signal On Warning Chime
The turn signal on warning chime warns that the vehicle traveled for more than 0.8 km (0.5 miles) with the turn signals continuously on.
The chime stops sounding when the turn signal switch is placed in the OFF position, or when the ignition switch is placed in the OFF or ACC position.
The turn signal warning chime inputs are the:
- Ignition switch RUN/START position
- Turn signal switch ON position signal from the turn signal switch
- Odometer rolling count data from the ABS module
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, the headlamp switch is in the HEADLAMPS or PARKING LAMPS ON position, and the ignition key is in the OFF/LOCK position.
The chime stops sounding when any one of the above conditions are removed.
The headlamps on warning chime inputs are the:
- Ignition switch RUN/START position
- Door ajar signal from the driver door ajar switch
- Parking lamps on/off signal from the headlamp switch
Air Bag Warning Chime
The air bag warning chime warns that a fault is present in the Supplemental Restraint System (SRS). When a fault is present in the SRS, the Lighting Control Module (LCM) receives a request from the RCM and sounds the air bag warning chime. If a fault is present in the SRS when the ignition switch is placed in the ON position, the air bag warning chime sounds only after 90 seconds after the key cycle.
The air bag warning chime inputs are the:
- Ignition switch RUN/START position
- Air bag warning chime request signal from the RCM
Message Center Warning Chime
The message center warning chime sounds when a warning message is displayed on the message center. If multiple warning messages are present, a chime tone sounds for each of the warnings that are displayed.
The chime inputs are the warning messages displayed on the message center.
Fail Safe Cooling Warning Chime
When the engine coolant temperature reaches an over-temperature condition, the PCM provides an over-temperature signal to the IC. The IC positions the temperature gauge in the HOT range and illuminates the engine coolant over-temperature warning indicator. The IC also provides an intermittent chime, consisting of 3 tones within a 5-second interval for level 1 fail safe cooling mode or 5 tones within a 9-second interval for level 2 fail safe cooling mode.
The chime input is the fail safe cooling chime request from the PCM.