Raider V6-3.7L SOHC (2006)
ABS Light: Description and Operation
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is standard equipment on all instrument clusters. This indicator serves both the standard equipment Rear
Wheel Anti-Lock (RWAL) and optional equipment 4-Wheel Anti-Lock (4WAL) brake systems. This indicator is located near the upper edge of the
instrument cluster, between the tachometer and the speedometer.
The ABS indicator consists of a stencil-like cutout of the International Control and Display Symbol icon for "Failure of Anti-lock Braking System" 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 icon to appear in amber through the
translucent outer layer of the overlay when the indicator is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic
circuit board. The ABS indicator is serviced as a unit with the instrument cluster.
OPERATION
The ABS indicator gives an indication to the vehicle operator when the ABS system is faulty or inoperative. 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 Controller Antilock
Brake (CAB) over the Controller Area Network (CAN) data bus. The ABS 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 ABS indicator for
the following reasons:
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Bulb Test - Each time the ignition switch is turned to the On position the ABS indicator is illuminated for about four seconds as a bulb test. The
entire bulb test is a function of the CAB.
-
ABS Lamp-On Message - Each time the cluster receives a lamp-on message from the CAB, the ABS indicator will be illuminated. The indicator
remains illuminated until the cluster receives a lamp-off message from the CAB, or until the ignition switch is turned to the Off position,
whichever occurs first.
-
Communication Error - If the cluster receives no lamp-on or lamp-off messages from the CAB for five consecutive message cycles, the ABS
indicator is illuminated. The indicator remains illuminated until the cluster receives a valid message from the CAB, or until the ignition switch is
turned to the Off position, whichever occurs first.
-
Actuator Test - Each time the instrument cluster is put through the actuator test, the ABS indicator will be turned on, then off again during the
bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.
-
ABS Diagnostic Test - The ABS indicator is blinked on and off by lamp-on and lamp-off messages from the CAB during the performance of the
ABS diagnostic tests.
The CAB continually monitors the ABS circuits and sensors to decide whether the system is in good operating condition. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument cluster. If the CAB sends a lamp-on message after the bulb test, it indicates that the CAB has detected a
system malfunction and/or that the ABS system has become inoperative. The CAB will store a Diagnostic Trouble Code (DTC) for any malfunction it
detects. Each time the ABS indicator fails to light due to an open or short in the cluster ABS indicator circuit, the cluster sends a message notifying the
CAB of the condition, then the instrument cluster and the CAB will each store a DTC.
For proper diagnosis of the antilock brake system, the CAB, the CAN data bus, or the electronic message inputs to the instrument cluster that control the
ABS indicator, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.
