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5 - 52
BRAKES - ABS
BRAKES - ABS (Continued)
CAUTION
CAUTIONS
The ABS uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits.
CAUTION: In testing for open or short circuits, do
not ground or apply voltage to any of the circuits
unless instructed to do so for a diagnostic proce-
dure.
CAUTION: These circuits should only be tested
using a high impedance multi-meter or the DRBIII
scan tool as described in this section. Power
should never be removed or applied to any control
module with the ignition in the ON position. Before
removing or connecting battery cables, fuses, or
connectors, always turn the ignition to the OFF
position.
CAUTION: The CAB 24-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
CAUTION: This vehicle utilizes active wheel speed
sensors. Do not apply voltage to wheel speed sen-
sors at any time.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of aftermarket electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, etc.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS, do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.
CAUTION: If welding work is to be performed on the
vehicle, using an electric arc welder, the CAB con-
nector should be disconnected during the welding
operation.
CAUTION: Many components of the ABS System
are not serviceable and must be replaced as an
assembly. Do not disassemble any component
which is not designed to be serviced.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
CAUTION: Brake fluid will damage painted surfaces.
If brake fluid is spilled on any painted surface,
wash off with water immediately.
DIAGNOSIS AND TESTING - INSPECTION AND
ROAD TEST
(1) Visually inspect the ABS for damaged or dis-
connected components and connectors.
(2) Verify the brake lamps are operational. If they
are not, repair them prior to continuing.
(3) Connect the DRBIII
Link Connector located under the instrument panel
to the right of the steering column. If the DRBIII
does not power-up, check the power and ground sup-
plies to the connector.
(4) Turn the ignition key to the ON position. Select
ANTILOCK BRAKES.
(5) Read and record any Diagnostic Trouble Codes
(DTCs). If any DTCs are present, refer to the appro-
priate chassis diagnostic information.
NOTE: Diagnostic trouble codes (DTCs) are kept in
the controller's memory until either erased by the
technician using the DRBIII , or erased automati-
cally after 3500 miles. DTCs are retained by the
controller even if the ignition is turned off or the
battery is disconnected. More than one DTC can be
stored at a time. When accessed, the number of
occurrences and the DTC that is stored are dis-
played.
If no problems are observed, it will be necessary to
road test the vehicle.
JR
scan tool to the Data
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