Dakota 2WD L4-2.5L VIN P (2001)
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 the DRB III 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 EMIC stay at zero
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All telltales on EMIC illuminate
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EMIC backlighting at full intensity
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Dashed lines in the Compass Mini-Trip Computer display
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No response received from any module on the PCI bus (except the PCM)
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No start (if equipped with Sentry Key immobilizer)
Symptoms of Individual module failure could include any one or more of the above. The difference would be that at least one or more modules
would respond to the DRB III.
Diagnosis starts with symptom identification. If a complete PCI Bus Communication Failure is suspected, begin by identifying which modules the
vehicle is equipped with and then attempt to get a response from the modules with the DRB III. If any modules are responding, the failure is not
related to the total bus, but can be caused by one or more modules PCI circuit or power supply and ground circuits. The DRB III may display
"BUS +/- SIGNAL OPEN" or "NO RESPONSE" to indicate a communication problem. These same messages will be displayed if the vehicle is
not equipped with that particular module. The CCD error message is a default message used by the DRB III and in no way indicates whether or not
the PCI bus is operational. The message is only an indication that a module is either not responding or the vehicle is not equipped.
VEHICLE THEFT SECURITY SYSTEM
The VTSS system monitors the door ajar switches, and ignition switch to detect unauthorized entry into the vehicle. Once the vehicle is "armed",
any one of these inputs can cause the VTSS system to be tripped. Once tripped, the horn and lights will pulse for 3 minutes and if an attempt is
made to start the engine with a non-programmed SKIM key, it will start and stall. If the trigger condition is still present, the lights will continue to
flash for an additional 15 minutes, after which the system Will stop pulsing the lights and return to the "armed" state. The cause of the last 4 alarm
triggers is stored by the CTM and may be retrieved by the DRB III . The system may be disarmed by either an unlock command from a valid RKE
key fob by using a key in either door, or by using a valid SKIM key in the ignition. The door key cylinders are equipped with disarm switches.
There is also a VTSS lamp on the dash that provides information to the driver about the state of the vehicle theft system.
WINDSHIELD WIPER SYSTEM
The AN or AN84 truck equipped with a higline CTM will utilize speed sensitive intermittent wipers. A base CTM will provide for intermittent
wipers without the speed sensitive feature. The low and high speeds are controlled through the wiper stalk switch. The intermittent portion of the
wiper control is handled by the CTM through the intermittent wiper relay. When the module detects a decrease in delay time as selected by the
driver, an immediate wipe of the windshield takes place and the new delay interval is implemented.
