Subaru Legacy 2004 Service Manual page 3128

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK OUTPUT OF ABS WHEEL SPEED
SENSOR USING SUBARU SELECT MONI-
TOR.
1) Select {Current Data Display & Save} in
Subaru Select Monitor.
2) Read the ABS wheel speed sensor output
corresponding to the faulty wheel in Subaru
Select Monitor data display mode.
2 CHECK POOR CONTACT IN CONNECTOR.
Turn the ignition switch to OFF.
3 CHECK SOURCES OF SIGNAL NOISE.
Make sure the car phone, radio wave device
like radio and etc., or electric device are
installed correctly.
4 CHECK SOURCES OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor har-
ness.
5 CHECK VDCCM&H/U.
1) Connect all the connectors.
2) Erase the memory.
3) Perform the inspection mode. <Ref. to
VDC(diag)-23, PROCEDURE, Inspection
Mode.>
4) Read the DTC.
6 CHECK OTHER DTC DETECTION.
7 CHECK INSTALLATION OF ABS WHEEL
SPEED SENSOR.
8 CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Install the ABS wheel speed sensor.
2) Prepare an oscilloscope.
3) Check ABS wheel speed sensor. <Ref. to
ABS-13, ABS WHEEL SPEED SENSOR,
INSPECTION, Front ABS Wheel Speed Sen-
sor.>
9 CHECK ABS WHEEL SPEED SENSOR OR
MAGNETIC ENCODER.
10 CHECK SOURCES OF SIGNAL NOISE.
Make sure the car phone, radio wave device
like radio and etc., or electric device are
installed correctly.
11 CHECK SOURCES OF SIGNAL NOISE.
Check if the noise sources are (such as an
antenna) installed near the sensor harness.
VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)
Check
Does the speed indicated on
the display change in response
to the speedometer reading
during acceleration/decelera-
tion when the steering wheel is
in the straight-ahead position?
Is there poor contact in con-
nectors between VDCCM&H/U
and ABS wheel speed sensor?
Are the car phone, radio wave
device like radio and etc., or
electric device installed cor-
rectly?
Are noise sources installed?
Is the same DTC displayed?
Is any other DTC displayed?
Is the ABS wheel speed sen-
sor installation bolt tightened
7.5 N'm (0.76 kgf-m, 5.5 ft-lb)?
Is the oscilloscope pattern the
same waveform as shown in
the figure when the tire is
rotated? Is the pattern as
shown in the figure displayed
regularly in the oscilloscope
when the tire is slowly rotated
more than one revolution with
even speed?
Are there foreign materials,
breakage or damage in the
protrusion of ABS wheel speed
sensor or magnetic encoder?
Is the car phone, radio wave
device like radio and etc., or
electric device installed cor-
rectly?
Are noise sources installed?
VDC(diag)-55
Yes
Go to step 2. Go to step 7.
Repair the con- Go to step 3.
nector.
Go to step 4. Install the radio
wave device and
electric device
properly.
Install the noise Go to step 5.
sources apart from
the sensor har-
ness.
Replace the Go to step 6.
VDCCM&H/U.
<Ref. to VDC-7,
VDC Control Mod-
ule & Hydraulic
Control Unit
(VDCCM&H/U).>
Perform the diag- It results from a
nosis according to temporary noise
DTC. interference.
Go to step 8. Tighten the ABS
wheel speed sen-
sor installation
bolts.
Go to step 9. Go to step 13.
Remove dirt thor- Go to step 10.
oughly. Replace
the ABS wheel
speed sensor or
magnetic encoder
as a unit with hub
unit bearing when
it is broken or
damaged.
Go to step 11. Install the radio
wave device and
electric device
properly.
Go to step 12. Install the noise
sources apart from
the sensor har-
ness.
No