Subaru Legacy 2003 Service Manual page 3068

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR
Step
1 CHECK HARNESS BETWEEN ECM AND VD-
CCM.
1) Turn ignition switch to OFF.
2) Disconnect connectors from VDCCM and
ECM.
3) Measure resistance between VDCCM and
ECM.
Connector & terminal
H4 engine RHD without OBD model
(F87) No. 45 — (B134) No. 24:
(F87) No. 75 — (B134) No. 25:
H4 engine RHD with OBD model
(F87) No. 45 — (B134) No. 32:
(F87) No. 75 — (B134) No. 33:
H4 engine LHD model
(F87) No. 45 — (B134) No. 24:
(F87) No. 75 — (B134) No. 25:
H6 engine model
(F87) No. 45 — (B136) No. 12:
(F87) No. 75 — (B136) No. 11:
Is the measured value less than the speci-
fied value?
2 CHECK GROUND SHORT OF HARNESS.
Measure resistance between VDCCM and
ECM.
Connector & terminal
(F87) No. 75 — Chassis ground:
(F87) No. 45 — Chassis ground:
Does the measured value exceed the specified
value?
3 CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between VDCCM and
chassis ground.
Connector & terminal
(F87) No. 75 — Chassis ground:
(F87) No. 45 — Chassis ground:
Is the measured value less than the speci-
fied value?
4 CHECK INPUT VOLTAGE TO ECM.
1) Turn ignition switch to OFF.
2) Connect connector to VDCCM.
3) Turn ignition switch to ON.
4) Measure voltage between ECM connector
and chassis ground.
Connector & terminal
H4 engine RHD without OBD model
(B134) No. 24 (+) — Chassis ground ( − − − − ):
(B134) No. 25 (+) — Chassis ground ( − − − − ):
H4 engine RHD with OBD model
(B134) No. 32 (+) — Chassis ground ( − − − − ):
(B134) No. 33 (+) — Chassis ground ( − − − − ):
H4 engine LHD model
(B134) No. 24 (+) — Chassis ground ( − − − − ):
(B134) No. 25 (+) — Chassis ground ( − − − − ):
H6 engine model
(B136) No. 12 (+) — Chassis ground ( − − − − ):
(B136) No. 11 (+) — Chassis ground ( − − − − ):
Is the measured value within the specified
range?
Value
0.5 Ω
1 MΩ
0.5 V
10 — 15 V
VDC-95
VDC (DIAGNOSTICS)
Yes
Go to step 2. Repair or replace
open circuit
between VDCCM
and ECM.
Go to step 3. Repair or replace
ground short cir-
cuit between
VDCCM and ECM.
Go to step 4. Repair or replace
battery short cir-
cuit between
VDCCM and ECM.
Go to step 6. Go to step 5.
No