Subaru Impreza 2003 Service Manual page 2522

DIAGNOSTICS PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ABS (DIAGNOSTICS)
Step
12 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. 29 (+) — Chassis
ground ( − − − − ):
RHD: (F49) No. 29 (+) — Chassis ground
( − − − − ):
13 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
14 CHECK ABSCM&H/U.
1)Connect all connectors.
2)Erase the memory.
3)Perform the inspection mode.
4)Read out the DTC.
15 CHECK ANY OTHER DTC APPEARANCE.
16 CHECK INPUT VOLTAGE OF LATERAL G
SENSOR.
1)Turn the ignition switch to OFF.
2)Remove the console box.
3)Remove the lateral G sensor from vehicle.
(Do not disconnect connector.)
4)Turn the ignition switch to ON.
5)Measure the voltage between lateral G sen-
sor connector terminals.
Connector & terminal
(B257) No. 1 (+) — No. 3 ( − − − − ):
17 CHECK OPEN CIRCUIT IN LATERAL G SEN-
SOR OUTPUT 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. 29 — No. 28:
RHD: (F49) No. 29 — No. 28:
18 CHECK LATERAL G SENSOR.
1)Connect the connector to lateral G sensor.
2)Connect the connector to ABSCM&H/U.
3)Turn the ignition switch to ON.
4)Measure the voltage between lateral G sen-
sor connector terminals.
Connector & terminal
(B257) No. 2 (+) — No. 3 ( − − − − ):
19 CHECK LATERAL G SENSOR.
Measure the voltage between lateral G sensor
connector terminals.
Connector & terminal
(B257) No. 2 (+) — No. 3 ( − − − − ):
Check
Is the voltage less than 1 V?
nector between ABSCM&H/U
and lateral G sensor?
Is the same DTC as in current
diagnosis still being output?
Are other DTCs being output? Proceed with the
Is the voltage 4.75 — 5.25 V? Go to step 17.
Is the resistance 5.0 — 5.6
kΩ?
Is the voltage 2.1 — 2.5 V
when lateral G sensor is in hor-
izontal position?
Is the voltage 3.3 — 3.7 V
when lateral G sensor is
inclined right to 90°?
ABS-182
Yes
Go to step 13. Repair the har-
ness between lat-
eral G sensor and
ABSCM&H/U.
Repair the con- Go to step 14.
nector.
Replace the Go to step 15.
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
A temporary poor
diagnosis corre- contact.
sponding to DTC.
Repair the har-
ness/connector
between Lateral G
sensor and
ABSCM&H/U.
Go to step 18. Repair the har-
ness/connector
between lateral G
sensor and
ABSCM&H/U.
Go to step 19. Replace the lateral
G sensor. <Ref. to
ABS-23, Lateral G
Sensor.>
Go to step 20. Replace the lateral
G sensor. <Ref. to
ABS-23, Lateral G
Sensor.>
No