Mitsubishi Eclipse Workshop Manual page 457

SERVICE BRAKES
-
Service
Adjustment
Procedures
35-53
o
o
Manually turning
the wheel
to
be
measured
by
1/2
to
'l
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
.
Speed sensor pole piece-to-rotor clearance
too
large
o
Faulty speed sensor
Then. in order
to
observe the output state
of the
wheel
speed sensors, shift into low gear (4WD vehicle) and drive
the wheels, observe the output voltage waveform
of
each
wheel speed sensor
with
an
oscilloscope.
In
the case of the 2WD 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.
4.
o
C
POINTS
IN
WAVEFORM MEASUREMENT
o
a
The
wheel speed sensor cable moves following motion of the front or
rear
suspension. Therefore,
itis
likely that it has an
open circuit only
when driving on rough
roads
ahd
it
functions normally
on
ordinary roads. lt
is,
therefore. recommended
to observe sensor output voltage waveform also under special conditions, such
as
rough
road driving.
'I
.Ä
,F
o
ü
Symptom Probable causes Remedy
Too small or zero
waveform
amplitude
Faulty
wheel speed sensor
Replace sensor
lncorrect pole piece-to-rotor clearance Adjust clearance
Waveform amplitude
f
luctuates
excessively (this
is no
problem
if
the
minimum amplitude is
100 mV
or more)
Axle
hub eccentric or
with
large
runout
Replage hub
Noisy or
disturbed
waveform
Open circuit
in
sensor Replace sensor
Open circuit in harness Correct harness
Incorrectly
mounted wheel speed sensor Mount correctly
Rotor
with
missing or damaged
teeth
Replace
rotor
NOTE
PWUE9010