Section 88 (Chime Warning System): Operation

The chime warning system components operate on battery voltage received through a fuse in the Junction Block (JB) on a non-switched fused B(+) circuit so that the system may operate regardless of the ignition switch position. The chime warning system also monitors the ignition switch position so that some chime features will only occur with ignition switch in the On position, while others occur regardless of the ignition switch position.

The chime warning system provides an audible indication to the vehicle operator or occupants under the following conditions:

• Airbag Indicator Warning  - The ElectroMechanical Instrument Cluster (EMIC) chime tone generator will generate one, short, chime when the ignition switch is in the On, position, and an electronic message is received over the Programmable Communications Interface (PCI) data bus from the Airbag Control Module (ACM) requesting "Airbag" indicator illumination. This warning will only occur following completion of the "Airbag" indicator bulb test, and will only, occur once during an ignition cycle. The ACM uses internal programming, hard wired inputs from the front Supplemental Restraint System (SRS) components and, on vehicles so equipped, electronic messages received over the PCI data bus from each Side Impact Airbag Control Module (SIACM) to determine the proper "Airbag" indicator messages to send to the EMIC.
• Anti-Lock Brake Indicator Warning  - The EMIC chime tone generator will generate one, short, chime when the ignition switch is in the On position, and an electronic message is received over the PCI data bus from the Controller Anti-lock Brake (CAB) requesting "Anti-Lock Brake, System (ABS)" indicator illumination. This warning will only occur following completion of the "ABS" indicator bulb test, and will only occur once during an ignition cycle. The CAB uses internal programming, hard wired inputs from the Anti-Lock Brake System (ABS) components, and electronic messages received over the PCI data bus from the Powertrain Control Module (PCM) to deter mine the proper "ABS" indicator messages to send to the EMIC.
• Compass Mini-Trip Computer Reset  - The EMIC chime tone generator will generate one, short, fixed duration chime when the ignition switch is in the On position, and an electronic message is received over the PCI data bus from the optional Compass Mini-Trip Computer (CMTC) requesting that the CMTC elapsed time, average fuel economy, and/or trip odometer data has been reset. The CMTC uses internal programming, hard wired inputs from the U.S./Metric and Reset switches, and electronic messages received from the Body Control Module (BCM) to determine the proper reset messages to send to the EMIC.
• Door Ajar Warning  - The EMIC chime tone generator will generate a single chime when the ignition switch is in the On position, and electronic messages are received over the PCI data bus from the Body Control Module (BCM) indicating that the status of any door ajar input has changed, and from the PCM indicating that the vehicle is moving. The BCM uses internal programming, and hard wired inputs from the door ajar switches and the ignition switch to determine the proper door ajar switch messages to send to the EMIC. The PCM uses internal programming and a hard wired vehicle speed pulse input received from the BCM to determine the proper vehicle distance messages to send to the EMIC.
• Electrical System Voltage Low or High Warning  - Each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate a single chime the first time an electronic message is received over the PCI data bus from the PCM requesting "Charging" indicator illumination. This warning would indicate that the monitored electrical system voltage is either too low or too high. This warning will only occur once during an ignition cycle. The PCM uses internal programming and hard wired inputs from the electrical and charging systems to determine the proper "Charging" indicator messages to send to the EMIC.
• Engine Coolant Temperature High Warning  - Each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate chime the first time an electronic message is received over the PCI data bus from the PCM indicating that the engine coolant temperature is too high. This chime will sound for five consecutive tones, unless an electronic message is received from the PCM indicating that the engine coolant temperature is not too high, or unless the ignition switch is turned to the Off position before the five tones have completed. The PCM uses internal programming and a hard wired input from the engine coolant temperature sensor to determine the proper engine coolant temperature messages to send to the EMIC.
• Engine Oil Pressure Low Warning  - Each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate a single chime the first time three sequential sets of electronic messages are received over the PCI data bus from the PCM indicating that the engine oil pressure is too low with the engine running. The PCM uses internal programming and hard wired inputs from the oil pressure sensor and the crankshaft position sensor to determine the proper oil pressure and engine speed messages to send to the EMIC.
• Fasten Seat Belt Warning  - Each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate repetitive chimes at a slow rate the first time an electronic message is received over the PCI data bus from the ACM requesting "Seatbelt" indicator illumination. The ACM uses internal programming and hard wired inputs from the driver side front seat belt switch and the ignition switch to determine that the driver side front seat belt is not fastened with the ignition switch in the On position. These chimes will continue to sound for a duration of about six seconds each time the ignition switch is turned to the On position, or until the driver side front seat belt is fastened, whichever occurs first. This audible warning occurs independent of the visual warning provided by the EMIC "Seatbelt" indicator.
• Gate Ajar Warning  - The EMIC chime tone generator will generate a single chime when the ignition switch is in the On position, and electronic messages are received over the PCI data bus from the BCM indicating that the status of the tailgate ajar input has changed from closed to not closed, and from the PCM indicating that the vehicle is moving. The BCM uses internal programming, and hard wired inputs from the tailgate ajar switch and the ignition switch to determine the proper tailgate ajar switch messages to send to the EMIC. The PCM uses internal programming and a hard wired vehicle speed pulse input received from the BCM to determine the proper vehicle distance messages to send to the EMIC.
• Glass Ajar Warning  - The EMIC chime tone generator will generate a single chime when the ignition switch is in the On position, and electronic messages are received over the PCI data bus from the BCM indicating that the status of the rear flip-up glass ajar input has changed from closed to not closed, and from the PCM indicating that the vehicle is moving. The BCM uses internal programming, and hard wired inputs from the flip-up glass ajar switch and the ignition switch to determine the proper flip-up glass ajar switch messages to send to the EMIC. The PCM uses internal programming and a hard wired vehicle speed pulse input received from the BCM to determine the proper vehicle distance messages to send to the EMIC.
• Head/Park/Fog Lights-On Warning  - The EMIC chime tone generator will generate repetitive chime at a fast rate when the ignition switch is in any position except On, and electronic messages are received over the PCI data bus from the BCM indicating that the exterior lights are On with the ignition switch in any position except On, and the status of the driver side front door is not closed. The BCM uses internal programming and hard wired inputs from the left (lighting) control stalk of the multifunction switch, the ignition switch, and the driver side front door ajar switch to determine the proper messages to send to the EMIC. These chimes will continue to sound until the exterior lighting is turned Off, until the ignition switch is turned to the On position, or until the status of the driver side front door ajar input changes from not closed to closed, whichever occurs first.
• Key-In-Ignition Warning  - The EMIC chime tone generator will generate repetitive chime at a fast rate when the ignition switch is in any position except On, and electronic messages are received over the PCI data bus from the BCM indicating that the key is in the ignition lock cylinder with the ignition switch in any position except On, and the driver side front door is not closed. The BCM internal programming and hard wired inputs from the key-in ignition circuitry of the ignition switch, the ignition switch, and the driver side front door ajar switch to determine the proper messages to send to the EMIC. These chimes will continue to sound until the key is removed from the ignition lock cylinder, until the ignition switch is turned to the On position, or until the status of the driver side front door ajar input changes from not closed to closed, whichever occurs first.
• Low Coolant Warning  - On vehicles equipped with a diesel engine, the EMIC chime tone generator will generate a single chime when the ignition switch is first turned to the On position and a hard wired input from the engine coolant level sensor to the EMIC indicates that the coolant level is low for more than about one-quarter second. Any time after the ignition switch is first turned to the On position, the EMIC uses internal programming to check the status of the engine coolant level sensor inputs about once every second, then adjusts an internal counter up or down based upon the status of this input. When the counter accumulates thirty inputs indicating that the coolant level is low, a single chime is sounded. This strategy is intended to reduce the effect that coolant sloshing within the coolant reservoir can have on reliable chime warning operation. This warning will only occur once during an ignition cycle.
• Low Fuel Warning  - Each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate a single chime the first time an electronic message is received over the PCI data bus from the PCM requesting "Low Fuel" indicator illumination. The chime will only occur a second time during the same ignition cycle if another electronic message has been received from the PCM indicating that there is an increase in the fuel level equal to about 3 liters (0.8 gallon), then a subsequent electronic message from the PCM requests "Low Fuel" indicator illumination. This strategy combined with filtering performed by the internal programming of the PCM on the fuel tank sending unit input is intended to reduce the possibility of fuel sloshing within the fuel tank causing multiple low fuel warning chimes during a given ignition cycle. The EMIC will also respond with the low fuel warning chime when electronic fuel level messages are received from the PCM indicating that the hard wired input to the PCM from the fuel tank sending unit is an open circuit (greater than full), or a short circuit (less than empty).
• Low Washer Fluid Warning  - The EMIC chime tone generator will generate a single chime when the ignition switch is turned to the On position and a hard wired input from the washer fluid level switch to the EMIC indicates the washer fluid is low for more than about ?one-quarter second. Any time after the ignition switch is first turned to the On position, the EMIC uses internal programming to check the status of the washer fluid level switch inputs about once every-second, then adjusts an internal counter up or down based upon the status of this input. When the counter accumulates thirty inputs indicating that the washer fluid level is low, a single chime is sounded. This strategy is intended to reduce the effect that' fluid sloshing within the washer reservoir can have: on reliable chime warning operation. This warning will only occur once during an ignition cycle.
• Overspeed Warning  - The EMIC chime tone generator will generate repetitive chimes at a slow rate when the ignition switch is in the On position, and an electronic message received over the PCI data bus from the PCM indicates that the vehicle speed is over a programmed speed value. The PCM uses internal programming and distance pulse information received over a hard wired vehicle speed pulse input from the BCM to determine the proper vehicle speed messages to send to the EMIC. The BCM uses an internally programmed electronic pinion factor and a hard wired input from the rear wheel speed sensor to calculate the proper distance pulse information to send to the PCM. The electronic pinion factor represents the proper tire size and axle ratio information for the vehicle. These chimes will continue to sound until the vehicle speed messages are below the programmed speed value, or until the ignition switch is turned to the Off position, whichever occurs first. The overspeed warning feature is only enabled on a BCM that has been programmed with a Middle East Gulf Coast Country (GCC) country code.
• No Airbag Indicator Message Warning  - The EMIC chime tone generator will generate one, short, chime and turn on the "Airbag" indicator when the ignition switch is in the On position, and a PCI data bus "Airbag" indicator on or off message is not received from the ACM for six consecutive seconds.
• No Anti-Lock Brake Indicator Message Warning  - The EMIC chime tone generator will generate one, short, chime and turn on the "ABS" indicator when the ignition switch is in the On position, arid a PCI data bus "ABS" indicator on or off message is not received from the CAB for six consecutive seconds.
• No Fuel Level Message Warning  - The EMIC chime tone generator will generate one, short, chime and turn on the "Low Fuel" indicator when the ignition switch is in the On position, and a PCI data bus fuel level message is not received from the PCM for twelve consecutive seconds.
• Remote Keyless Entry Transmitter Programming  - On vehicles so equipped, the EMIC chime tone generator will generate a single chime when an electronic message is received over the PCI data bus from the BCM indicating that a Remote Keyless Entry (RKE) transmitter has been successfully programmed by the customer into the RKE module memory.
• Sentry Key Immobilizer System Transponder Programming  - On vehicles so equipped, the EMIC chime tone generator will generate a single chime when an electronic message is received over PCI data bus message from the Sentry Key Immobilizer Module (SKIM) indicating that the Sentry Key Immobilizer System (SKIS) has been placed in the "Customer Learn" programming mode, and again each time a new SKIS transponder has been successfully programmed by the customer.
• Turn Signal Cancel Warning  - The EMIC chime tone generator will generate repetitive chimes at a slow rate when the vehicle is driven for a distance of about 3.2 kilometers (about two miles) with a turn signal indicator flashing. The EMIC uses an electronic message received over the PCI data bus from the PCM, and a hard wired input from the turn signal switch circuitry of the multifunction switch to determine when to sound the turn signal cancel warning. The PCM uses internal programming and distance pulse information received over a hard wired vehicle speed pulse input from the BCM to determine the proper vehicle speed messages to send to the EMIC. The BCM uses an internally programmed electronic pinion factor and a hard wired input from the rear wheel speed sensor to calculate the proper distance pulse information to send to the PCM. The electronic pinion factor represents the proper tire size and axle ratio information for the vehicle. These chimes will continue to sound until the turn signal is turned Off, until the hazard warning system is turned On, or until the ignition switch is turned to the Off position, whichever occurs first.
• Water-In-Fuel Warning  - On vehicles equipped with a diesel engine, each time the ignition switch is turned to the On position, the EMIC chime tone generator will generate a single chime the first time an electronic message is received over the PCI data bus from the PCM requesting "Water-in-Fuel" indicator illumination. The PCM uses internal programming and a hard wired input from the water-in-fuel sensor to determine the proper water-in-fuel messages to send to the EMIC. This warning will only occur once during an ignition cycle.

The EMIC provides chime service for all available features in the chime warning system. The EMIC relies upon its internal programming and hard wired inputs from the turn signal (multifunction) switch, the washer fluid level switch, and the engine coolant level sensor (diesel engine only) to provide chime service for the turn signal cancel warning, the low washer fluid warning, and the low coolant warning respectively. The EMIC relies upon electronic message inputs received from other electronic modules over the PCI data bus network to provide chime service for all of the remaining chime warning system features. Upon receiving the proper inputs, the EMIC activates the chime tone generator to provide the audible chime warning to the vehicle operator. The internal programming of the EMIC determines the priority of each chime request input that is received, as well as the rate and duration of each chime tone that is to be generated. See the owner's manual in the vehicle glove box for more information on the features provided by the chime warning system.

The hard wired chime warning system inputs to the EMIC, as well as other hard wired circuits for this system may be diagnosed and tested using conventional diagnostic tools and procedures. However, conventional diagnostic methods may not prove conclusive in the diagnosis of the EMIC, the PCI data bus network, or the electronic message inputs used by the EMIC to provide chime warning system service. The most reliable, efficient, and accurate means to diagnose the EMIC, the PCI data bus network, and the electronic message inputs for the chime warning system requires the use of a DRBIII(R) scan tool. Refer to BODY DIAGNOSTIC PROCEDURES .