Subaru Forester 2004 Service Manual page 115

Diagnostics Procedure with Diagnostic Trouble Code (DTC)
ABS (DIAGNOSTIC)
Step
9 CHECK ABS WHELL SPEED SENSOR GAP.
Measure the tone wheel to ABS wheel speed
sensor piece gap over entire perimeter of
wheel.
10 PREPARE OSCILLOSCOPE.
11 CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Raise all four wheels off ground.
2) Turn the ignition switch to OFF.
3) Connect the oscilloscope to the connector.
4) Turn the ignition switch to ON.
5) Rotate the wheels and measure voltage at
specified frequency. <Ref. to ABS-17, WAVE-
FORM, Control Module I/O Signal.>
NOTE:
When this inspection is completed, the AB-
SCM&H/U sometimes stores DTC 29 or DTC
56.
Connector & terminal
DTC 22
LHD: (B6) No. 1 (+) — No. 2 (
RHD: (F95) No. 1 (+) — No. 2 (
DTC 24
LHD: (F103) No. 6 (+) — No. 7 (
RHD: (F94) No. 1 (+) — No. 2 (
DTC 26
LHD: (B98) No. 6 (+) — No. 19 (
RHD: (B98) No. 28 (+) — No. 29 (
DTC 28
LHD: (B98) No. 17 (+) — No. 18 (
RHD: (B98) No. 25 (+) — No. 26 (
12 CHECK CONTAMINATION OF ABS WHEEL
SPEED SENSOR OR TONE WHEEL.
Remove the disc rotor or drum from hub in
accordance with DTC.
13 CHECK DAMAGE OF ABS WHEEL SPEED
SENSOR OR TONE WHEEL.
Check
Is the gap the following value?
Front wheel:
0.3 — 0.8 mm
(0.012 — 0.031 in)
Rear wheel:
0.7 — 1.2 mm
(0.028 — 0.047 in)
Is an oscilloscope available?
Is oscilloscope pattern as
shown in the figure? <Ref. to
ABS-17, WAVEFORM, Con-
trol Module I/O Signal.>
−
):
−
):
−
):
−
):
−
):
−
):
−
):
−
):
Is the ABS wheel speed sen-
sor piece or tone wheel con-
taminated by dirt or other
foreign matter?
Are there broken or damaged
in the ABS wheel speed sen-
sor piece or tone wheel?
ABS-114
Yes
Go to step 10. Adjust the gap.
NOTE:
Adjust the gap us-
ing spacer (Part
No. 26755AA000).
If the spacers can-
not correct gap, re-
place worn ABS
wheel speed sen-
sor or worn tone
wheel.
Go to step 11. Go to step 12.
Go to step 15. Go to step 12.
Thoroughly Go to step 13.
remove dirt or
other foreign mat-
ter.
Replace the ABS Go to step 14.
wheel speed sen-
sor or tone wheel.
Front: <Ref. to
ABS-15, Front
ABS Wheel Speed
Sensor.> Rear:
<Ref. to ABS-18,
Rear ABS Wheel
Speed Sensor.>
and Front: <Ref. to
ABS-21, Front
Tone Wheel.>
Rear: <Ref. to
ABS-22, Rear
Tone Wheel.>
No