Subaru Forester 2004 Service Manual page 58

Diagnostics Procedure without Diagnostic Trouble Code (DTC)
Step
1 CHECK INSTALLATION OF ABS WHEEL
SPEED SENSOR.
Turn the ignition switch to OFF.
2 CHECK ABS WHEEL SPEED SENSOR GAP.
Measure the gap between ABS wheel speed
sensor piece and tone wheel.
3 PREPARE OSCILLOSCOPE.
4 CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Lift-up the vehicle.
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 ABSCM
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 (
5 CHECK CONTAMINATION OF ABS WHEEL
SPEED SENSOR OR TONE WHEEL.
Remove the disc rotor or drum from hub in
accordance with DTC.
Check
Are the ABS wheel speed sen-
sor installation bolts tightened
33 N·m (3.4 kgf-m, 24.6 ft-lb)?
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 an oscilloscope pattern
snooth, as shown in the figure?
<Ref. to ABS-17, WAVE-
FORM, Control Module I/O
Signal.>
−
):
−
):
−
):
−
):
−
):
−
):
−
):
−
):
Is the ABS wheel speed sen-
sor piece or the tone wheel
contaminated by dirt or other
foreign matter?
ABS-57
ABS (DIAGNOSTIC)
Yes
Go to step 2. Tighten the ABS
wheel speed sen-
sor installation
bolts securely.
Go to step 3. Adjust the gap.
NOTE:
Adjust the gap us-
ing spacer (Part
No. 26755AA000).
If the spacer can-
not correct gap, re-
place worn ABS
wheel speed sen-
sor or worn tone
wheel.
Go to step 4. Go to step 5.
Go to step 8. Go to step 7.
Thoroughly Go to step 6.
remove dirt or
other foreign mat-
ter.
No