Mitsubishi 1992 3000GT, Service Manual

Page: 901 / 1308

SERVICE BRAKES On-vehicle Service
Body harness
MB991 356
tor
When turned manually
I
L---~---t---*--
I
,
,
5. Replace shoe and lining assembly or brake disc if very
irregular contact area is observed.
NOTE
Clean off chalk after check.
WHEEL SPEED SENSOR OUTPUT VOLTAGE
MEASUREMENT
1. Lift up the vehicle and release the parking brake.
2. Disconnect the ECU harness connector and measure
with the adapter harness (MB991356) connected to the
harness side connector.
Caution
1. Never insert a probe, etc. into the connector as
it may result in poor contact later.
2. Do not connect the connector (Special Tool)
marked with except when recording the wave-
form on a driving test. In such a case, connect
the connector to the ECU.
Terminal
No.
(same for
AWD
and
FWD)
3. Manually turning the wheel to be measured by to
1 turn/second, measure the output voltage with a circuit
tester or oscilloscope.
Output voltage:
When measured with circuit tester: 70 or more
When measured with oscilloscope (max. voltage):
100 or more
Probable causes of low output voltage
l
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 similarly it will be higher as the wheel speed
increases.
TSB Revision