Subaru 2009 IMPREZA, Service Manual

Page: 2414 / 3619

ABS(diag)-34
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ABS (DIAGNOSTICS)
Step Check Yes No
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 defective ABS wheel speed sen-
sor output.
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? Go to step 2 . Go to step 7 .
2 CHECK POOR CONTACT OF CONNECTOR.
Turn the ignition switch to OFF.
Is there poor contact of connec-
tors between ABSCM&H/U and
ABS wheel speed sensor? Repair the connec-
tor. Go to step 3 .
3 CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.
Are the radio wave devices and
electronic components
installed correctly? Go to step 4 . Install the radio
wave devices and
electronic compo-
nents properly.
4 CHECK CAUSE OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor harness.
Are noise sources installed? Install the noise
sources apart from
sensor harness. Go to step 5 .
5 CHECK ABSCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to ABS(diag)-21,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
ABS(diag)-20, Inspection Mode.>
4) Read the DTC.
Is the same DTC displayed? Replace the
ABSCM only. <Ref.
to ABS-8,
REPLACEMENT,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).> Go to step 6 .
6 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed? Check DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
ABS(diag)-26, List
of Diagnostic Trou-
ble Code (DTC).> It results from a
temporary noise
interference.
7 CHECK INSTALLATION OF ABS WHEEL
SPEED SENSOR. Is the ABS wheel speed sensor
installation bolt tightened 7.5
N·m (0.76 kgf-m, 5.5 ft-lb)? Go to step 8 . Tighten the ABS
wheel speed sen-
sor installation
bolts.
8 CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Install the ABS wheel speed sensor.
2) Prepare an oscilloscope.
3) Check the ABS wheel speed sensor. <Ref.
to ABS-14, ABS WHEEL SPEED SENSOR,
INSPECTION, Front ABS Wheel Speed Sen-
sor.>
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 one rotation or more? Go to step 10 . Go to step 9 .
9 CHECK ABS WHEEL SPEED SENSOR OR
MAGNETIC ENCODER. Are there foreign matter, break-
age or damage at the tip of ABS
wheel speed sensor or mag-
netic encoder? Remove dirt thor-
oughly. Also
replace the ABS
wheel speed sen-
sor or magnetic
encoder as a unit
with hub unit bear-
ing if it is broken or
damaged. Go to step 10 .
10 CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.
Are the radio wave devices and
electronic components
installed correctly? Go to step 11 . Install the radio
wave devices and
electronic compo-
nents properly.