Subaru Legacy 2002 Service Manual page 2353

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR
ABS (Diagnostics)
No.
1 CHECK IF THE WHEELS HAVE TURNED
FREELY FOR A LONG TIME.
2 CHECK TIRE SPECIFICATIONS.
Turn ignition switch to OFF.
3 CHECK WEAR OF TIRE.
4 CHECK TIRE PRESSURE.
5 CHECK INSTALLATION OF ABS SENSOR.
Tightening torque:
32±10 N·m (3.3±1.0 kgf-m, 24±7 ft-lb)
6 CHECK ABS SENSOR GAP.
Measure tone wheel to ABS sensor piece gap
over entire perimeter of the wheel.
Specifications
Front wheel
0.3 — 0.8 mm (0.012 — 0.031 in)
Rear wheel
0.44 — 0.94 mm (0.0173 — 0.0370 in)
7 PREPARE OSCILLOSCOPE.
8 CHECK ABS SENSOR SIGNAL.
1) Raise all four wheels of ground.
2) Turn ignition switch OFF.
3) Connect the oscilloscope to the connector.
4) Turn ignition switch ON.
5) Rotate wheels and measure voltage at
specified frequency. <Ref. to ABS-15,
WAVEFORM, Control Module I/O Signal.>
NOTE:
When this inspection is completed, the
ABSCM&H/U sometimes stores the DTC 29.
Connector & terminal
(B62) No. C5 (+) — No. B5 (−) (Front
RH):
(B62) No. C6 (+) — No. B6 (−) (Front
LH):
(F55) No. 1 (+) — No. 2 (−) (Rear RH):
(F55) No. 4 (+) — No. 5 (−) (Rear LH):
9 CHECK CONTAMINATION OF ABS SEN-
SOR OR TONE WHEEL.
Remove disc rotor from hub.
Step
Check if the wheels have
been turned freely for more
than one minute, such as
when the vehicle is jacked-
up, under full-lock corner-
ing or when tire is not in
contact with road surface.
Are the tire specifications
correct?
Is the tire worn exces-
sively?
Is the tire pressure correct? Go to step 5.
Are the ABS sensor instal-
lation bolts tightened
securely?
Is the gap within the speci-
fications?
Is an oscilloscope avail-
able?
Is oscilloscope pattern
smooth, as shown in fig-
ure?
Is the ABS sensor piece or
the tone wheel contami-
nated by dirt or other for-
eign matter?
ABS-52
Check Yes
The ABS is nor-
mal. Erase the
DTC.
NOTE:
When the wheels
turn freely for a
long time, such as
when the vehicle
is towed or
jacked-up, or
when steering
wheel is continu-
ously turned all
the way, this
trouble code may
sometimes occur.
Go to step 3.
Replace tire.
Go to step 6.
Go to step 7.
Go to step 8.
Go to step 12.
Thoroughly
remove dirt or
other foreign mat-
ter.
No
Go to step 2.
Replace tire.
Go to step 4.
Adjust tire pres-
sure.
Tighten ABS sen-
sor installation
bolts securely.
Adjust the gap.
NOTE:
Adjust the gap
using spacer (Part
No. 26755AA000).
If spacers cannot
correct the gap,
replace worn sen-
sor or worn tone
wheel.
Go to step 9.
Go to step 9.
Go to step 10.