Subaru Impreza 2003 Service Manual page 2375

DIAGNOSTICS PROCEDURE WITHOUT DIAGNOSTIC TROUBLE CODE (DTC)
Step
2 CHECK GROUND TERMINAL.
Measure the resistance between Ground ter-
minals (B81) and chassis ground.
Terminals
Ground terminal (A) — Chassis ground:
Ground terminal (B) — Chassis ground:
3 CHECK DIAGNOSIS LINE.
1)Connect the Ground terminal (B81) to diag-
nosis connector (B82) No. 6.
2)Disconnect the connector from ABSCM&
H/U.
3)Measure the resistance between
ABSCM&H/U connector and chassis ground.
Connector & terminal
LHD: (B301) No. 4 — Chassis ground:
RHD: (F49) No. 4 — Chassis ground:
4 CHECK GENERATOR.
1)Start the engine.
2)Idle the engine.
3)Measure the voltage between generator and
chassis ground.
Terminals
Generator B terminal (+) — Chassis
ground ( − − − − ):
5 CHECK BATTERY TERMINAL.
Turn the ignition switch to OFF.
6 CHECK POWER SUPPLY OF ABSCM.
1)Start the engine.
2)Idle the engine.
3)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
( − − − − ):
7 CHECK WIRING HARNESS.
1)Disconnect the connector (i2) from connec-
tor (B37).
2)Turn the ignition switch to ON.
8 CHECK PROJECTION AT ABSCM&H/U.
1)Turn the ignition switch to OFF.
2)Check for damage at the ABSCM&H/U ter-
minal.
NOTE:
For detail of connector switch, refer to follow-
ing. <Ref. to ABS-13, ELECTRICAL SPECIFI-
CATION, Control Module I/O Signal.>
9 CHECK ABSCM&H/U.
Measure the resistance between ABSCM&H/U
terminals.
Terminals
No. 22 — No. 23:
Check
Is the resistance less than 0.5
Ω?
Is the resistance less than 0.5
Ω?
Is the voltage 10 — 15 V?
Is there poor contact at battery
terminal?
Is the voltage 10 — 15 V?
Does the ABS warning light
turn on?
Is there any damage on projec-
tion which switches connector
switch?
Is the resistance more than 1
MΩ?
ABS-35
ABS (DIAGNOSTICS)
Yes
Go to step 3. Repair the open
circuit in Ground
terminal harness.
Go to step 4. Repair the open
circuit in harness
connector
between
ABSCM&H/U and
diagnosis connec-
tor.
Go to step 5. Repair the genera-
tor. <Ref. to
SC(H4SO)-14,
Generator.>
Repair or tighten Go to step 6.
the battery termi-
nal.
Go to step 7. Repair the
ABSCM&H/U
power supply cir-
cuit.
Repair the front or Go to step 8.
body wiring har-
ness.
Replace the Go to step 9.
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
Go to step 10. Replace the
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
No