2007 Commander XK Factory Service Manual 8 - ELECTRICAL

GEAR SELECTOR INDICATOR

DESCRIPTION



An electronic automatic transmission gear selector indicator is standard factory-installed equipment on this vehicle. However, on vehicles not equipped with an optional automatic transmission, this indicator is electronically disabled. The gear selector indicator information is displayed in the upper left corner within the fixed segment Organic Light Emitting Diode (OLED) display unit. This OLED display unit is soldered onto the cluster electronic circuit board, and is visible through a window with a smoked clear lens located on the lower edge of the speedometer dial face of the cluster overlay. The dark lens over the OLED display unit prevents the indicator from being clearly visible when it is not illuminated.

The gear selector indicator displays the following characters from left to right: P, R, N, and a fourth, reconfigurable character. The reconfigurable character can be a letter D or the numbers 1 through 4. Each character appears in a blue-green color and at the same lighting level as the odometer information. Respectively, these characters represent the PARK, REVERSE, NEUTRAL and each of the forward drive gear positions of the transmission gear selector lever on the floor panel transmission tunnel. The indicator also illuminates brackets [ ] on each side of the character that represents the currently selected lever position.

During daylight hours (exterior lamps are OFF) the fixed segment OLED is illuminated at full brightness for clear visibility. At night (exterior lamps are ON), the OLED lighting level is adjusted with the other cluster general illumination lamps using the panel lamps dimmer function of the interior lighting control sleeve on the left multi-function switch control stalk. However, a PARADE mode position of the control sleeve allows the OLED to be illuminated at full brightness if the exterior lamps are turned ON during daylight hours.

The gear selector indicator is serviced as a unit with the fixed segment OLED display unit in the instrument cluster.

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 fixed segment Organic Light Emitting Diode (OLED) display unit soldered onto the instrument cluster electronic circuit board, and the OLED will not display the gear selector indicator information after the ignition switch is turned 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:

  • Selected Gear Message - Each time the cluster receives an electronic selected gear message from the PCM, brackets [ ] will be illuminated around the appropriate character in the gear selector indicator. The brackets will remain illuminated until the cluster receives a different selected gear message, or until the ignition switch is turned to the OFF position, whichever occurs first.
  • Communication Error - If the cluster fails to receive a selected gear message from the PCM within three seconds, the instrument cluster circuitry will display all gear selector positions bracketed (selected) until a valid selected gear message is received or until the ignition switch is turned to the OFF position, whichever occurs first.
  • Actuator Test - Each time the cluster is put through the actuator test, the odometer fixed segment OLED will display all of its characters at once to confirm the functionality of the OLED and the cluster control circuitry.

The PCM continually monitors a hard wired multiplex input from the Transmission Range Sensor (TRS), then sends the proper message to the ElectroMechanical Instrument Cluster (EMIC).

For proper diagnosis of the TRS, the PCM, the EMIC, the CAN data bus or the electronic communication related to gear selector indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.