Dakota 4WD V8-4.7L (2009)
Transmission Shift Position Indicator Lamp: Description and Operation
Transmission Range Indicator - Operation
OPERATION
The electronic gear selector indicator gives an indication to the vehicle operator of the transmission gear that has been selected with the automatic
transmission gear selector lever. This indicator is controlled by the instrument cluster circuit board based upon cluster programming and electronic
messages received from the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus.
The gear selector indicator information is displayed by the odometer/trip odometer Vacuum Fluorescent Display (VFD) unit soldered onto the instrument
cluster electronic circuit board, and the VFD will not display the gear selector indicator information after the ignition switch turns to the off position.
Each time the cluster is disconnected from battery current for more than about five minutes, it must configure itself for the automatic transmission type
that is in the vehicle once it is reconnected to battery current. The instrument cluster circuitry operates the gear selector indicator to provide the following
features:
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Selected Gear Message - Each time the cluster receives an electronic selected gear message from the PCM, a box illuminates around the
appropriate character in the gear selector indicator. The box remains illuminated until the cluster receives a different selected gear message, or
until the ignition switch turns to the off position, whichever occurs first.
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Communication Error - If the cluster fails to receive a selected gear message from the PCM within three seconds, the instrument cluster circuitry
displays all gear selector positions boxed (selected) until a valid selected gear message is received or until the ignition switch turns to the off
position, whichever occurs first.
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Self Test - Each time the cluster is put through the self test, the odometer/trip odometer VFD displays all of its characters at once, then step
through each character segment individually during the VFD portion of the test to confirm the functionality of the VFD and the cluster control
circuitry.
The PCM continually monitors a hardwired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the instrument
cluster, also known as the Cab Compartment Node (CCN). For further diagnosis of the gear selector indicator or the instrument cluster circuitry that
controls this function, See: Instrument Cluster / Carrier/Testing and Inspection/Component Tests and General Diagnostics.
Use a diagnostic scan tool for proper diagnosis of the TRS, the PCM, the CCN, the CAN data bus or the electronic communication related to gear
selector indicator operation. Refer to the appropriate diagnostic information.
