Bendix Commercial Vehicle Systems EC-14 ANTILOCK CONTROLLER 5/04 - Manual (Page 21)

21
TROUBLESHOOTING
SECTION VIII PART A
TESTING THE WHEEL SPEED SENSOR
Pass magnet over “RESET”
on EC-14 ™ controller. Remove
magnet and observe the LEDs
Are any red LEDs
illuminated?
NO
Go to Section VIII Part B
and begin testing
YES
Turn ignition off and check the following:
A. Remove connector(s) from EC-14 ™ controller and measure resistance
between appropriate speed sensor signal (+) and signal return (-).
Resistance for Bendix
® WS-20 ™ speed sensor should be between 1500-
2500 ohms. Refer to vehicle maintenance manual if other than the WS-20 ™
speed sensor is in use. If resistance not correct, disconnect connector at
speed sensor. Inspect connector, then check resistance between pins on
sensor. If resistance is not correct (between 1500-2500 ohms for the Bendix
®
WS-20 ™ speed sensor), replace sensor, otherwise proceed to step B.
B. Check “gap” between speed sensor and exciter or tone ring. (Gap for Bendix ®
WS-20 ™ speed sender is between 0 - .015 inches.) If sensor gap must be
adjusted, check for loose or worn wheel bearings before re-gapping sensor.
Refer to vehicle maintenance manual for worn bearings.
C. If sensor gap is correct check wheel bearing for free play to verify it complies
to manufacturer’s recommendations.
D. Make certain exciter or tone ring is in place and inspect condition. Check for
missing or damaged teeth and that it runs true and perpendicular to sensor
face.
E. Check wiring harness and connectors that run to sensor.
F.
Check for dragging brakes (over-adjusted, trapped air in actuator, out-of-
round drums, faulty return springs, parking brake system faults, etc.) and
correct. Retest.
RESETTING
EC-14 ™ CONTROLLER
3C
RT. REAR
3D
RT. REAR
3H
LFT.
FRONT
3J
LFT. FRONT
2C
LFT. REAR
3E
LFT. REAR
3K
RT. FRONT
2H
RT. FRONT
Reconnect EC-14 ™ controller connector, turn
ignition on and pass magnet over “RESET” on
EC-14 ™ controller and remove. Observe LEDs
Are any red LEDs
illuminated?
Go to Section IV
“Inspection for Illuminated
Red LEDs” and retest
YES
NO
Repeat the “Initial Start-up
Procedure”
MAGNET
HERE
Testing Speed Sensor Resistance
EC-14 ™ Controller Wire Harness Connector
START HERE