Grand Cherokee 2WD V8-4.7L VIN J (2004)
EVIC CHIME REQUESTED MESSAGES
When the following messages are displayed the EVIC will send a chime request to the BCM. The BCM will respond with a series of chimes.
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Turn signal on for more than 1.0 mile
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Service reminder
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Coolant level low
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Washer fluid low
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Tire Pressure Monitoring System alert messages (if equipped)
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Door or liftgate ajar (when critical speed is reached)**
SENTRY KEY IMMOBILIZER SYSTEM
The Sentry Key Immobilizer System (SKIS) also uses tactile beep support from the chime warning system. The Sentry Key Immobilizer Module
(SKIM) is programmed to send chime request messages over the Programmable Communications Interface (PCI) data bus to the Body Control
Module (BCM) to provide audible confirmation that:
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the SKIM has been successfully placed in the Customer Learn mode.
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A new Sentry key transponder has been successfully programmed by the SKIM. See the owner's manual in the vehicle glove box for more
information on the features, use and operation of the SKIS. For diagnostic information, refer to the Powertrain Diagnostic Information.
Communication
The Programmable Communication Interface or PCI Bus is a single wire multiplexed network capable of supporting binary encoded messages shared
between multiple modules. The PCI bus circuit is identified as D25. The modules are wired in parallel. Connections are made in the harness using
splices. The following modules are used on the WJ/WG:
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Body Control Module
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Adjustable Pedals Module
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Door Modules (Driver & Passenger)
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Airbag Control Module
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Controller Antilock Brake
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Powertrain Control Module
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Engine Control Module (Diesel)
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Radio
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CD Changer
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Transmission Control Module
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Automatic Zone Control Module
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Sentry Key Immobilizer Module
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Seat Module
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Electronic Vehicle Information Center
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Mechanical Instrument Cluster
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Shifter Assembly (Diesel)
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Rain Sensor
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Power Amplifier
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Intrusion Transceiver Module (Export)
Each module provides its own bias and termination in order to transmit and receive messages. The bus voltage is at zero volts when no modules are
transmitting and is pulled up to about seven and a half volts when modules are transmitting.
The bus messages are transmitted at a rate averaging 10800 bits per second. Since there is only voltage present when the modules transmit and the
message length is only about 500 milliseconds, it is ineffective to try and measure the bus activity with a conventional voltmeter. The preferred method
is to use DRBIII(R) lab scope. The 12v square wave selection on the 20-volt scale provides a good view of the bus activity. Voltage on the bus should
pulse between zero and about seven and a half volts. Refer to the following figure for some typical displays.