Grand Cherokee 2WD V8-4.7L VIN N (2000)
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 figure for some typical displays.
The PCI Bus failure modes are broken down into two categories. Complete PCI Bus Communication Failure and individual module no response.
Causes of complete PCI Bus Communication Failure include a short to ground or battery on the PCI circuit. Individual module no response can be
caused by an open circuit at either the Diagnostic Junction Port or the module, or an open battery or ground circuit to the affected module.
Symptoms of a complete PCI Bus Communication Failure would include but are not limited to:
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All gauges on the MIC stay at zero
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All telltales on MIC illuminate
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MIC backlighting at full intensity
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Dashed lines in the EVIC ambient temperature display
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No response received from any module on the PCI bus
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No start (if equipped with Sentry Key Immobilizer)
