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GENERAL INFORMATION
the recommended pressures for optimum system
operation. Variation in wheel and tires size or
significant variations in inflation pressure can pro-
duce inaccurate wheel speed signals; however, the
system will continue to function when using the
correct factory mini-spare.
3.3.5 SYSTEM INITIALIZATION
System initialization starts when the key is
turned to "run". At this point, the CAB performs a
complete self-check of all electrical components in
the antilock systems.
Between 8-17 km/h (5-10 mph}, a dynamic test is
performed. This will momentarily cycle the inlet
and outlet valves, check wheel speed sensor cir-
cuitry and run the pump motor at 25 km/h (15
mph), the CAB will try to test the pump motor. If
the brake pedal is depressed the test will be run at
40 km/h (24 mph) regardless of brake switch state.
If, during the dynamic test, the brake pedal is
depressed the driver may feel the test through
brake pedal pulsations. This is a normal condition.
If any component exhibits a trouble condition
during system initialization or dynamic check, the
CAB will illuminate the ABS warning indicator and
TCS indicator (if equipped).
3.3.6 DIAGNOSTIC MODE
To enter diagnostic mode, a vehicle speed must be
below 10 km/h (6 mph) and no ABS/TCS condition
present. If vehicle speed is not below 10 km/h (6
mph), a "No Response" message could be displayed
by the DRBIII . The following are characteristics of
diagnostic mode:
– The amber ABS warning indicator will blink
rapidly. If a hard trouble code, such as CAB
Power Feed Circuit Failure code is present, the
indicator will be illuminated without blinking
until the trouble condition is cleared.
– Antilock operation is disabled.
– Valve actuation with the DRBIII® is disabled
when the vehicle speed is above 8 km/h (5
mph). If valve actuation is attempted above 8
km/h (5 mph), a "No Response" message will be
displayed on the DRBIII .
3.4 DIAGNOSTIC TROUBLE CODES
The Controller Antilock Brake may report any of
several Diagnostic Trouble Codes (DTC)s.
3.5 FREEZE FRAME
Freeze Frame takes a "snapshot" of specific vehi-
cle information the instant an ABS failure is recog-
nized and stores this information into the CAB
memory. This information can be accessed using the
DRBIII to help diagnose the fault. Freeze Frame
will capture the first time failure or only a new
failure that occurs during the current ignition cycle.
3.6 DRBIII ERROR MESSAGES AND
BLANK SCREEN
Under normal operation, the DRBIII will dis-
play one of only two error messages:
– User-Requested
Requested COLD Boot
This is a sample of such an error message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err:0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.6.1 DRBIII DOES NOT POWER UP
If the LED's do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
connector cavity 16). A minimum of 11 volts is
required to adequately power the DRBIII .
If all connections are proper, and the vehicle
battery is fully charged, an inoperative DRBIII
may be the result of faulty cable or vehicle wiring.
3.6.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
4
WARM
Boot
or
User-
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