Subaru Impreza 2003 Service Manual page 2397

DIAGNOSTICS PROCEDURE WITHOUT DIAGNOSTIC TROUBLE CODE (DTC)
Step
11 CHECK GROUND SHORT OF HARNESS.
Measure the resistance between ABSCM&H/U
connector and chassis ground.
Connector & terminal
DTC 22
LHD: (B301) No. 11 — Chassis ground:
RHD: (F49) No. 11 — Chassis ground:
DTC 24
LHD: (B301) No. 9 — Chassis ground:
RHD: (F49) No. 9 — Chassis ground:
DTC 26
LHD: (B301) No. 14 — Chassis ground:
RHD: (F49) No. 14 — Chassis ground:
DTC 28
LHD: (B301) No. 7 — Chassis ground:
RHD: (F49) No. 7 — Chassis ground:
12 CHECK GROUND CIRCUIT OF ABSCM&H/U.
Measure the resistance between ABSCM&H/U
and chassis ground.
Connector & terminal
LHD: (B301) No. 23 — Chassis ground:
RHD: (F49) No. 23 — Chassis ground:
13 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
14 CHECK SOURCES OF SIGNAL NOISE.
15 CHECK SOURCES OF SIGNAL NOISE.
16 CHECK SHIELD CIRCUIT.
1)Disconnect the connectors (B303) and
(F62).
2)Measure the resistance between shield con-
nector and chassis ground.
Connector & terminal
DTC 22
LHD: (B303) No. 2 — Chassis ground:
RHD: (F62) No. 2 — Chassis ground:
DTC 24
LHD: (B303) No. 1 — Chassis ground:
RHD: (F62) No. 1 — Chassis ground:
NOTE:
If the DTC is 26, 28: Go to YES.
17 CHECK ABSCM&H/U.
1)Connect all connectors.
2)Erase the memory.
3)Perform the inspection mode.
4)Read out the DTC.
Check
Is the resistance more than 1
MΩ?
Is the resistance less than 0.5
Ω?
nectors between ABSCM&H/U
and ABS wheel speed sensor?
Is the car telephone or wireless
transmitter properly installed?
Are noise sources (such as an
antenna) installed near the
sensor harness?
Is the resistance less than 0.5
Ω?
Is the same DTC as in current
diagnosis still being output?
ABS-57
ABS (DIAGNOSTICS)
Yes
Go to step 12. Repair the har-
ness/connector
between
ABSCM&H/U and
ABS wheel speed
sensor.
Go to step 13. Repair the
ABSCM&H/U
ground harness.
Go to step 14. Repair the con-
nector.
Go to step 15. Properly install the
car telephone or
wireless transmit-
ter.
Go to step 16. Install the noise
sources apart from
sensor harness.
Go to step 17. Repair the shield
harness.
Replace the Go to step 18.
ABSCM&H/U.
<Ref. to ABS-7,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>
No