35-70SERVICE BRAKES- Service Adjustment Procedures
I, ! I ! I4 IO II IIWhen turned manually :---;---i-.-l---L--.I 8 ! IaI 1 11 1 II ’I 1’ I I I;-;--1---:--‘---+---t---i ’I IL---)-.-i---+--.II ’ I I 1 , 1 ,I
--:--~---;---:---~--~--
POINTS IN WAVEFORM MEASUREMENT
3. Manually turning the wheel to be measured by
l/2 to 1
turn/second, measure the output voltage with a circuit
tester or oscilloscope. Output voltage: When measured with circuit tester: 70
mV or more
When measured with oscilloscope (max. voltage): 100
mV or more
Probable causes of low output voltage
0 Speed sensor pole piece-to-rotor clearance too large
l Faulty speed sensor
4. Then, in order to observe the output state of the wheel
speed sensors, shift into low gear
(AWD vehicle) and drive
the wheels, observe the output voltage waveform of each
wheel speed sensor with an oscilloscope.
In the case of the FWD vehicle, observe the waveform with
an oscilloscope; for the front wheels, shift into low gear and
drive the wheels; for the rear wheels, turn the wheels manually at a constant speed.
NOTE
1.Waveform may also be observed by actually driving the
vehicle.
2.The output voltage is low when the wheel speed is low
and increases as the wheel speed increases.
Symptom
Too small or zero waveform amplitude Probable causes
Faulty wheel speed sensor Remedy
Replace sensor
Incorrect pole piece-to-rotor clearanceAdjust clearance
Waveform amplitude fluctuates Axle hub eccentric or with large runoutReplace hub
excessively (this is no problem if
the minimum amplitude is 100 mVor more)
Noisy or disturbed waveformOpen circuit in sensor Replace
sensor
Open circuit in harness
Correct harness
Incorrectly mounted wheel speed sensorMount correctly
Rotor with missing or damaged teeth Replace rotor
NOTEThe wheel speed sensor cable moves following motion of the front or rear\
suspension. Therefore, it is likely that it
has anopen circuit only when driving on rough roads and it functions normally \
on ordinan/ roads. It is, therefore, recommended
to observe sensor output voltage waveform also under special conditions,\
such as rough road dnvlng.
TSB Revision
INSPECTION OF HYDRAULIC UNIT
INSPECTION BY FEEL
(1) Jack up the vehicle and support the vehicle with rigid racks
placed at the specified jack-up points.
(2) Release the parking brake and determine the drag force(drag torque) of each wheel by feel.
(3) Set the scan tool through the adapter harness
(MB991 377)
as illustrated.
(4) After confirming that the shift lever or selector lever is in the neutral position, start the engine.
The ABS warning light lights up, it goes into the scan tool mode. In the scan tool mode, ABS does not function.
I
35-130 SERVICE BRAKES - Wheel Speed Sensor
Left side viewRight side
U 14AOO45
Left side view Left side
lo. INSTALLATION OF REAR SPEED SENSOR
(1) Temporarily install the speed sensor to the rear axle
spindle.
Caution Be careful when handling the pole piece at the tip of
the speed sensor and the toothed edge of the rotor so as not to damage them by striking against metal
objects.
(2) Note the following points when connecting the speed
sensor cable, and secure the cable by the clip.
0 Secure the clip so that the white-painted part
(shaded in the illustration) of the speed sensor
cable is not twisted.
0 Be sure that there is space (where shown in the illustration) so that the trailing arm and speed
sensor cable do not contact, and then secure by
the clip.
Caution
Because there is the
possibiliti of damage to the
cable during driving if the speed sensor cable and
the trailing arm come into contact, or if the speed sensor cable is twisted, care must be taken regard-
ing this point.
(3)
Inset-t a feeler gauge into the space between the
speed sensor’s pole piece and the rotor’s toothed
surface, and then tighten the speed sensors at the position where the clearance is the standard value.
Standard value:
0.3-0.9 mm (.012--035 in.)
NOTE
Check to be sure that there is no contact of the speed
sensor’s pole piece and the rotor’s toothed surface
when the rear hub assemlby is slowly rotated one
time.
If there is contact, it is probable that the rotor or the
rear hub is installed incorrectly, recheck installation.
10. INSTALLATION OF REAR SPEED SENSOR
Install the rear speed sensors as shown in the illustration.
Cross-section A-A
TSB Revision
Parkingcable
’ 2Rear speed
sensor1240076
Cross-section B-B Cross-section C-C
Rear speedsensor
