Subaru LEGACY 2003 Service Manual page 80

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR
ABS (DIAGNOSTICS)
7 CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
(F49) No. 6 (+) — Chassis ground ( − − − − ):
Is the measured value less than the speci-
fied value?
8 CHECK GROUND SHORT OF HARNESS.
Measure resistance between ABSCM&H/U
connector and chassis ground.
Connector & terminal
(F49) No. 28 — Chassis ground:
Does the measured value exceed the specified
value?
9 CHECK G SENSOR.
1) Turn ignition switch to OFF.
2) Remove G sensor from vehicle.
3) Connect connector to G sensor.
4) Connect connector to ABSCM&H/U.
5) Turn ignition switch to ON.
6) Measure voltage between G sensor con-
nector terminals.
Connector & terminal
(R70) No. 2 (+) — No. 3 ( − − − − ):
Is the measured value within the specified
range when G sensor is horizontal?
10 CHECK G SENSOR.
Measure voltage between G sensor connector
terminals.
Connector & terminal
(R70) No. 2 (+) — No. 3 ( − − − − ):
Is the measured value within the specified
range when G sensor is inclined forward to
90°?
11 CHECK G SENSOR.
Measure voltage between G sensor connector
terminals.
Connector & terminal
(R70) No. 2 (+) — No. 3 ( − − − − ):
Is the measured value within the specified
range when G sensor is inclined backward to
90°?
12 CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connector between
ABSCM&H/U and G sensor?
13 CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the DTC.
Is the same DTC still being output?
Step Value
1 V
1 MΩ
2.1 - 2.5 V
3.7 - 4.1 V
0.5 - 0.9 V
There is no poor contact.
Same DTC is not indicated.
ABS-78
Yes
Go to step 8. Repair harness
between G sensor
and ABSCM&H/U.
Go to step 9. Repair harness
between G sensor
and ABSCM&H/U.
Replace
ABSCM&H/U.
<Ref. to ABS-6,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
Go to step 10. Replace G sen-
sor. <Ref. to ABS-
21, G Sensor.>
Go to step 11. Replace G sen-
sor. <Ref. to ABS-
21, G Sensor.>
Go to step 12. Replace G sen-
sor. <Ref. to ABS-
21, G Sensor.>
Go to step 13. Repair connector.
Go to step 14. Replace
ABSCM&H/U.
<Ref. to ABS-6,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
No