Bendix Commercial Vehicle Systems WS-24 ANTILOCK WHEEL SPEED SENSOR - Manual (Page 4)

4
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make certain
all components and systems are restored to their
proper operating condition.
11. For vehicles with Antilock Traction Control (ATC),
the ATC function must be disabled (ATC indicator
lamp should be ON) prior to performing any vehicle
maintenance where one or more wheels on a drive
axle are lifted off the ground and moving.
REMOVAL
1. Unplug the cable assembly connector from its lead. Lift
the lock tab and pull on the connector until it disengages.
2. Gently pry the sensor and clamping sleeve from the
mounting block.
INSPECTION
Look for any visible damage to the sensor, cable assembly,
connector, mounting block, and foundation brake. Repair
or replace any damaged components. Make sure the block
is securely attached to the axle housing.
SENSOR INSTALLATION
1. For increased corrosion protection we recommend that
a high-temperature rated silicon- or lithium-based grease
be applied to the interior of the mounting block, the
sensor, and to a new clamping sleeve.
2. Install the new clamping sleeve fully into the block, with
the retaining tabs toward the inside of the vehicle.
3. Gently push (DO NOT STRIKE) the sensor into the
mounting block hole until it bottoms out on the face of
the tone ring. Secure the cable lead wire to the knuckle/
axle housing 3-6 inches from the sensor.
4. Apply a moderate amount of dielectric non-conductive
grease to both the sensor connector and harness
connector.
5. Engage the connectors, and push together until the lock
tab snaps into place.
NOTE: It is important for the wheel bearings to be adjusted
per the manufacturer's recommendations.
Excessive wheel end play can result in antilock
function shutdown in cases where the sensor is
pushed too far away from the tone ring.
ELECTRICAL TESTING
1. Before testing the speed sensor, its location on the
vehicle should be confirmed using the Troubleshooting
or Start Up procedure for the specific antilock controller
in use. (See the Service Data Sheet for the antilock
controller for this procedure.)
2. Proceed to the sensor in question and inspect its wiring
connector. Disconnect the connector and test the
resistance between the pins ON THE SENSOR.
Normal resistance range across pins at room temperature
should be 1500-2000 Ohms. (Note: Previous model
WS-20
™ sensor was rated at 2000-2500 Ohms.)
Individually test the resistance of each pin to vehicle ground
and note there is NO CONTINUITY.
If the resistance readings are as shown, the wire harness
leading to the modulator may require repair or replacement.
Before attempting repair or replacement of the wire harness,
refer to the test procedures specified for the antilock
controller in use for possible further testing that may be
required to substantiate the wire harness problem. If the
resistance values are NOT AS STATED, replace the sensor.
Resistance could be as low as 1100 Ohms or as high as
3300 Ohms if wheel end has recently been exposed to
extreme temperature.
OPERATIONAL TESTING
To test sensor operation, one of two tests can be done.
TEST 1
Drive the vehicle in a safe area to a minimum speed of 15
mph. Be sure to apply the vehicle brakes several times.
Then stop the vehicle and check the LED display on the
Bendix controller. If the dash light is out and the sensor
LED(s) are not illuminated, the sensor is installed properly.
TEST 2
Disconnect the connector from the sensor's socket or from
the attached lead. Raise the vehicle wheel so it rotates
easily. Connect a volt-Ohm meter (set to read Volts AC) to
the pins on the sensor or lead and spin the wheel. If the
wheel is spun at 1/2 revolution per second the reading
should be greater than 0.250 VAC.
If the sensor fails to operate as described, check the wiring
from the controller to the sensor. Make sure all connectors
are properly and tightly installed. Check for frayed or
damaged wires and check and/or reset the sensor air gap
(distance from sensor tip to exciter ring) as described in
this manual. For additional troubleshooting information, see
the troubleshooting procedure for the specific antilock
system in use.
BW2364 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 9/2004. Printed in U.S.A.