Patriot 4WD L4-2.4L (2009)
During daylight hours, (exterior lamps are off) the odometer VFD unit illuminates at full brightness for clear visibility. At night (exterior lamps are on),
the VFD lighting level adjusts with the other cluster illumination lamps using the panel lamps dimmer thumbwheel of the headlamp switch on the
instrument panel. However, a Parade mode position of the thumbwheel allows the VFD unit to illuminate at full brightness if the exterior lamps are
turned on during daylight hours.
The no-bus indicator is serviced as a unit with the odometer VFD unit in the instrument cluster.
No Bus Indicator - Operation
OPERATION
The no-bus indicator gives an indication to the vehicle operator when the electronic communication data bus is ineffective. This indicator is controlled
by the instrument cluster logic circuit based upon cluster programming and electronic messages not being received over the Controller Area Network
(CAN) data bus from the Front Control Module (FCM).
The no-bus indicator function of the odometer Vacuum Fluorescent Display (VFD) unit is completely controlled by the instrument cluster logic circuit.
This logic only allows the indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start)
circuit. Therefore, the odometer VFD no-bus indicator is always off when the ignition switch is in any position except ON or START. The instrument
cluster turns ON the no bus indicator for the following reasons:
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No Electronic Communication Messages - Each time the ignition switch is turned to the ON position and the cluster does not receive electronic
communication messages over the CAN data bus, the no-bus indicator illuminates. The indicator remains illuminated until CAN bus
communication is restored or until the ignition switch turns to the OFF position, whichever occurs first.
The instrument cluster, also known as the Cab Compartment Node (CCN) continually monitors the CAN data bus to determine the status of many
sensors and systems throughout the vehicle. If bus communication is interrupted, the CCN cannot provide accurate displays and outputs.
Use a diagnostic scan tool is required for proper diagnosis of the no-bus indicator, the CCN, the CAN data bus or the electronic communication related
to no-bus indicator operation. Refer to the appropriate diagnostic information.
Service 4WD Indicator - Description
DESCRIPTION
A service 4WD indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional four-wheel drive system,
this indicator is electronically disabled. This indicator is located near the lower edge of the cluster overlay, between the speedometer and the tachometer.
The service 4WD indicator consists of a stencil-like cutout of the text 4WD! in the opaque layer of the instrument cluster overlay. The dark outer layer
of the overlay prevents the indicator from being clearly visible when it is not illuminated. An amber Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the indicator to appear in amber through the translucent outer layer of the overlay when it is illuminated from behind
by the LED, which is soldered onto the instrument cluster electronic circuit board.
The service 4WD indicator is serviced as a unit with the instrument cluster.
Service 4WD Indicator - Operation
OPERATION
The service 4WD indicator gives an indication to the vehicle operator when the Constantly Variable Transmission Control Module (CVTCM) has
recorded a Diagnostic Trouble Code (DTC) for an Electronically Controlled Coupling (ECC) circuit or component malfunction. This indicator is
controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from
the CVTCM over the Controller Area Network (CAN) data bus.
The service 4WD indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow
this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the
LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The instrument cluster will turn ON the service 4WD indicator for the following reasons:
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Bulb Test - Each time the ignition switch is turned to the ON position the service 4WD indicator is illuminated for about two seconds as a bulb
