Subaru Impreza 2003 Service Manual page 2423

DIAGNOSTICS PROCEDURE WITHOUT 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)Run the engine at idle.
4)Measure the voltage between ABSCM&H/U
connector and chassis ground.
Connector & terminal
LHD:
(B301) No. 1 (+) — Chassis ground ( − − − − ):
(B301) No. 24 (+) — Chassis ground ( − − − − ):
RHD:
(F49) No. 1 (+) — Chassis ground ( − − − − ):
(F49) No. 24 (+) — Chassis ground ( − − − − ):
2 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:
3 CHECK VALVE RELAY IN ABSCM&H/U.
Measure the resistance between ABSCM&H/U
and terminals.
Terminals
No. 23 — No. 24:
4 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
5 CHECK ABSCM&H/U.
1)Connect all connectors.
2)Erase the memory.
3)Perform the inspection mode.
4)Read out the DTC.
6 CHECK ANY OTHER DTC APPEARANCE.
Check
Is the voltage 10 — 15 V?
Is the resistance less than 0.5
Ω?
Is the resistance more than 1
MΩ?
nectors between generator,
battery and ABSCM&H/U?
Is the same DTC as in the cur-
rent diagnosis still being out-
put?
Are other DTCs being output? Proceed with the
ABS-83
ABS (DIAGNOSTICS)
Yes
Go to step 2. Repair the har-
ness connector
between battery,
ABS relay and
ABSCM&H/U.
Go to step 3. Repair the
ABSCM&H/U
ground harness.
Go to step 4. 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 5.
nector.
Replace the Go to step 6.
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