Subaru Legacy 2004 Service Manual page 3016

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., electric components are
installed correctly.
4 CHECK SOURCES OF SIGNAL NOISE.
Check that the noise sources are (such as an
antenna) installed near the sensor harness.
5 CHECK ABSCM&H/U.
1) Connect all the connectors.
2) Erase the memory.
3) Perform the inspection mode. <Ref. to
ABS(diag)-17, CLEAR MEMORY MODE,
OPERATION, Subaru Select Monitor.>
4) Read the DTC.
6 CHECK ANY OTHER DTC ON DISPLAY.
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 AND
MAGNETIC ENCODER.
10 CHECK SOURCES OF SIGNAL NOISE.
Make sure the car phone, radio wave device
like CB and etc., electric components are
installed correctly.
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 ABSCM&H/U
and ABS wheel speed sensor?
Is the car phone, radio wave
device like radio and etc., elec-
tric components installed cor-
rectly?
Is the noise sources installed? Install the noise
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)?
Does the oscilloscope indicate
the waveform pattern like
shown in the figure when the
tire is slowly turned? Does the
oscilloscope indication repeat
the waveform pattern like
shown in the figure when the
tire is slowly turned in equal
speed for more one rotation?
Is there foreign particles,
breakage or damage in the
pole piece of ABS wheel speed
sensor or magnetic encoder?
Is the car phone, radio wave
device like radio and etc., elec-
tric components installed cor-
rectly?
ABS(diag)-49
ABS (DIAGNOSTICS)
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 compo-
nents properly.
Go to step 5.
sources apart from
the sensor har-
ness.
Replace the Go to step 6.
ABSCM only.
<Ref. to ABS-8,
REPLACEMENT,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&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 10. Go to step 9.
Remove dirt com- Go to step 10.
pletely. 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 compo-
nents properly.
No