Subaru Impreza 2003 Service Manual page 2495

DIAGNOSTICS PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK INPUT VOLTAGE OF ABSCM&H/U.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ABSCM&
H/U.
3)Turn the ignition switch to ON.
4)Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD: (B301) No. 25 (+) — Chassis
ground ( − − − − ):
RHD: (F49) No. 25 (+) — Chassis ground
( − − − − ):
2 CHECK GROUND CIRCUIT OF MOTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between
ABSCM&H/U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 26 — Chassis ground:
RHD: (F49) No. 26 — Chassis ground:
3 CHECK INPUT VOLTAGE OF ABSCM&H/U.
1)Run the engine at idle.
2)Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD: (B301) No. 1 (+) — Chassis ground
( − − − − ):
RHD: (F49) No. 1 (+) — Chassis ground
( − − − − ):
4 CHECK GROUND CIRCUIT OF ABSCM&H/U.
1)Turn the ignition switch to OFF.
2)Measure the resistance between
ABSCM&H/U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 23 — Chassis ground:
RHD: (F49) No. 23 — Chassis ground:
5 CHECK MOTOR OPERATION.
Operate the sequence control. <Ref. to ABS-
10, ABS Sequence Control.>
NOTE:
Use the diagnosis connector to operate se-
quence control.
6 CHECK POOR CONTACT IN CONNECTORS.
Turn the ignition switch to OFF.
7 CHECK ABSCM&H/U.
1)Connect all connectors.
2)Erase the memory.
3)Perform the inspection mode.
4)Read out the DTC.
8 CHECK ANY OTHER DTC APPEARANCE.
Check
Is the voltage 10 — 15 V?
Is the resistance less than 0.5
Ω?
Is the voltage 10 — 15 V?
Is the resistance less than 0.5
Ω?
Can motor revolution noise
(buzz) be heard when carrying
out the sequence control?
Is there poor contact in con-
nector between generator, bat-
tery and ABSCM&H/U?
Is the same DTC as in current
diagnosis still being output?
Are other DTCs being output? Proceed with the
ABS-155
ABS (DIAGNOSTICS)
Yes
Go to step 2. Repair the har-
ness/connector
between battery
and ABSCM&H/U
and check fuse
SBF8.
Go to step 3. Repair the
ABSCM&H/U
ground harness.
Go to step 4. Repair the har-
ness connector
between battery,
ignition switch and
ABSCM&H/U.
Go to step 5. Repair the
ABSCM&H/U
ground harness.
Go to step 6. Replace the
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
Repair the con- Go to step 7.
nector.
Replace the Go to step 8.
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.
No