Subaru Forester 2004 Service Manual page 93

Diagnostics Procedure without Diagnostic Trouble Code (DTC)
ABS (DIAGNOSTIC)
Step
1 CHECK ALL FOUR WHEELS FOR FREE
TURNING.
2 CHECK SPECIFICATIONS OF ABSCM&H/U.
Check the specifications of the mark to the
ABSCM&H/U.
CO: AT
CP: MT
3 CHECK INPUT VOLTAGE OF G SENSOR.
1) Turn the ignition switch to OFF.
2) Remove the console box.
3) Remove the G sensor from vehicle. (Do not
disconnect the connector.)
4) Turn the ignition switch to ON.
5) Measure the voltage between G sensor
connector terminals.
Connector & terminal
(B292) No. 1 (+) — No. 3 (
4 CHECK OPEN CIRCUIT IN G SENSOR OUT-
PUT HARNESS AND GROUND HARNESS.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ABSCM&
H/U.
3) Measure the resistance between
ABSCM&H/U connector terminals.
Connector & terminal
LHD: (B301) No. 6 — No. 28:
RHD: (F49) No. 6 — No. 28:
5 CHECK GROUND SHORT IN G SENSOR
OUTPUT HARNESS.
1) Disconnect the connector from G sensor.
2) Measure the resistance between
ABSCM&H/U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 6 — Chassis ground:
RHD: (F49) No. 6 — Chassis ground:
6 CHECK BATTERY SHORT OF HARNESS.
Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD: (B301) No. 6 (+) — Chassis ground
−
( ):
RHD: (F49) No. 6 (+) — Chassis ground
−
( ):
7 CHECK BATTERY SHORT OF HARNESS.
1) Turn the ignition switch to ON.
2) Measure the voltage between ABSCM&H/
U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 6 (+) — Chassis ground
−
( ):
RHD: (F49) No. 6 (+) — Chassis ground
−
( ):
Have the wheels been turned
freely such as when the vehicle
is lifted up, or operated on a
free roller or rolling road?
Does the vehicle specification
and ABSCM&H/U specifica-
tion match?
Is the voltage 4.75 — 5.25 V? Go to step 4.
−
):
Is the resistance 5.0 — 5.6
kΩ?
Is the resistance more than 1
MΩ?
Is the voltage less than 1 V?
Is the voltage less than 1 V?
ABS-92
Check
The ABS is nor-
mal. Erase the
DTC.
Go to step 3.
Go to step 5.
Go to step 6.
Go to step 7.
Go to step 8.
Yes No
Go to step 2.
Replace the
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
Repair the har-
ness connector
between G sensor
and ABSCM&H/U.
Repair the har-
ness connector
between G sensor
and ABSCM&H/U.
Repair the har-
ness between G
sensor and
ABSCM&H/U.
Repair the har-
ness between G
sensor and
ABSCM&H/U.
Repair the har-
ness between G
sensor and
ABSCM&H/U.