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GENERAL INFORMATION
3.2 DIAGNOSTIC TROUBLE CODES
The Teves Mark 20i Antilock Brake System (ABS)
module may report any of the following diagnostic
trouble codes:
•
Controller Failure
•
G Switch Not Processable
•
Left Front Sensor Circuit Failure
•
Left Front Sensor Signal Failure
•
Left Rear Sensor Circuit Failure
•
Left Rear Sensor Signal Failure
•
CAB Power Feed Circuit
•
System Over voltage
•
System Under voltage
•
Pump Motor Not Working Properly
•
Right Front Sensor Circuit Failure
•
Right Front Sensor Signal Failure
•
Right Rear Sensor Circuit Failure
•
Right Rear Sensor Signal Failure
Diagnostic trouble codes are retained in memory
until erased using the DRBIII , or automatically
erased after 255 key cycles.
3.2.1 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 brake systems.
At around 19 km/h (12 miles per hour), the pump
motor is briefly activated to ensure operation, and
wheel speed sensor circuitry is checked. If the brake
pedal is applied when the vehicle reaches 19 km/h
(12 mph), this check will be delayed until 40 km/h
(25 mph). If, during the dynamic test, the brake
pedal is applied, the driver may feel the test
through brake pedal pulsations. This is a normal
condition. Throughout the remainder of the drive
cycle, ongoing tests are performed, and the CAB
monitors ABS circuits for continuity.
If any component causes a diagnostic trouble code
during system initialization or dynamic check, the
CAB will illuminate the ABS warning indicator.
3.2.2 DIAGNOSTIC MODE
To enter diagnostic mode, vehicle speed must be
below 10 km/h (6 mph), a ''no response'' message
will be displayed by the DRBIII . The following are
characteristics of diagnostic mode:
•
The ABS warning indicator will flash. If a hard
diagnostic trouble code is present, such as a
Speed Sensor Circuit or Signal Failure trouble
code or CAB Power Feed Circuit diagnostic trou-
ble code, the indicator will be illuminated without
blinking and limited diagnostic operations only
will be available until the diagnostic trouble code
condition is corrected.
•
Antilock operation is disabled.
3.2.3 INTERMITTENT DIAGNOSTIC
TROUBLE CODES
If the malfunction is not present while perform-
ing a test procedure, the diagnostic procedures will
not locate the problem. In this case, the code can
only suggest an area to inspect. Check for the
following:
•
loose or corroded connections
•
damaged components (sensors, tone wheels espe-
cially)
•
damaged wiring
•
excessive axle shaft runout
•
brake system hydraulic leaks
•
base brake system problems, non-ABS related.
If no obvious problems are found, erase diagnostic
trouble codes and, with the key on, wiggle the wire
harness and connectors. Recheck for codes periodi-
cally as you work through the system. This proce-
dure may uncover an intermittent or difficult to
locate malfunction.
3.3 AXLE LOCK
3.3.1 GENERAL
For this vehicle, the Axle Lock has no dedicated
module controller. A manual switch located on the
instrument panel controls the system. No DTC's
will occur for this system.
3.3.2 DESCRIPTION
The axle lock has the ability to lock the front and
rear axle differentials. The system components are
the instrument cluster, axle lock switch, front and
rear locker relays, front and rear locker pumps, and
locker indicator switches. To operate both lockers
three requirements need to be met:
1. ignition in the ON position
2. transfer case range sensor indicating 4 "LOW"
range
3. vehicle speed less than 16km/h (10 mph)
The 16km/h (10 mph) engagement is for engage-
ment only. All axles will remain locked if vehicle
speed does not exceed 72 km/h (45 mph).
The instrument cluster has the control logic that
monitors these requirements. If the requirements
are not met the axle lock switch will be disabled.
The axle lock switch receives the enable signals
from the instrument cluster. Any subsequent down-
4
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