Dakota 2WD V6-3.9L VIN X (1997)
ABS Light: Description and Operation
The amber anti-lock warning lamp is controlled by the vehicle's "smart" instrument cluster. This cluster has direct control over the Anti-Lock Brake
System (ABS) warning lamp. The cluster will periodically transmit a message over the Chrysler Collision Detection (CCD) bus relating to diagnostics
and current lamp status for the ABS lamp. If the Controller Anti-Lock Brake (CAB) does not receive this message for a period of three seconds, it will
assume that either the CCD bus or the instrument cluster is not operational and will turn on the red brake lamp in the event a fault is set. Likewise, the
cluster will expect a periodic message from the CAB indicating whether the lamp should be turned on or off. In the event that no signal is received from
the CAB for a certain number of ignition cycles, the cluster will turn on the ABS warning lamp. The lamp detects system related problems and indicates
the start of diagnostic action.
SYSTEM OPERATION
The Anti-Lock Brake System (ABS) lamp gives an indication when the ABS system is faulty or inoperative. The lamp is controlled by the
instrument cluster circuitry based upon messages received from the Controller Anti-lock Brake (CAB) on the Chrysler Collision Detection (CCD)
data bus. The lamp is turned on by the CAB for about two seconds when the ignition switch is turned to the On position as a bulb test.
After the bulb test, the CAB turns the lamp on or off based upon the results of the ABS self-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 message to the instrument cluster on the
CCD data bus to turn the lamp on or off. If the CAB turns the lamp on after the bulb test, it indicates that the CAB has detected a system
malfunction and/or that the ABS system has become inoperative. If only the amber ABS lamp is illuminated, and the red brake warning lamp
remains off, the base brake system will operate normally
Each time the instrument cluster circuitry receives a lamp-on message from the CAB, it will light the lamp for the duration of the ABS
malfunction. The CAB will also flash this lamp during the diagnostic mode, unless a hard fault is present. If a hard fault is present, the ABS lamp
will illuminate without flashing.
Rear Wheel Anti-Lock Brake System Lamp
The Rear Wheel Anti-Lock (RWAL) brake system lamp gives an indication when the RWAL system is faulty or inoperative. The lamp is
controlled by a hard-wired input to the instrument cluster from the RWAL Controller Anti-lock Brake (CAB). The lamp is turned on by the CAB
for about four seconds when the ignition switch is turned to the On position as a bulb test.
After the bulb test, the CAB turns the lamp on or off based upon the results of the RWAL system self-tests. The CAB continually monitors the
RWAL system circuits and sensors to decide whether the system is in good operating condition. The CAB then switches the ground circuit to the
lamp in the instrument cluster to turn the lamp on or off. If the CAB turns the lamp on after the bulb test, it indicates that the CAB has detected an
RWAL system malfunction and/or that the RWAL system has become inoperative. If only the amber RWAL lamp is illuminated, and the red brake
warning lamp remains off, the base brake system will operate normally.
