Subaru Legacy 2002 Service Manual page 2558

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR
No.
1 CHECK HARNESS BETWEEN ECM AND
VDCCM.
1) Turn ignition switch to OFF.
2) Disconnect connectors from VDCCM and
ECM.
3) Measure resistance between VDCCM and
ECM.
Connector & terminal
H4 ENGINE MODEL
(F87) No. 75 — (B134) No. 33:
(F87) No. 45 — (B134) No. 32:
H6 ENGINE MODEL
(F87) No. 75 — (B136) No. 11:
(F87) No. 45 — (B136) No. 12:
2 CHECK GROUND SHORT OF HARNESS.
Measure resistance between VDCCM and
ECM.
Connector & terminal
(F87) No. 75 — Chassis ground:
(F87) No. 45 — Chassis ground:
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:
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 MODEL
(B134) No. 33 (+) — Chassis ground
(−):
(B134) No. 32 (+) — Chassis ground
(−):
H6 ENGINE MODEL
(B136) No. 11 (+) — Chassis ground
(−):
(B136) No. 12 (+) — Chassis ground
(−):
5 CHECK POOR CONTACT IN ECM CON-
NECTORS.
6 ERASE MEMORY.
1) Connect all connectors.
2) Erase the memory.
Step
Is the resistance less than
0.5 Ω?
Is the resistance more than
1 MΩ?
Is the voltage less than 0.5
V?
Is the voltage between 10
and 15 V?
Is there poor contact in
ECM connector?
Can the memory be
erased?
VDC-99
Check Yes
Go to step 2.
Go to step 3.
Go to step 4.
Go to step 6.
Replace ECM. H4
ENGINE MODEL
<Ref. to FU-51,
Engine Control
Module.> or <Ref.
to FU(H6)-47,
Engine Control
Module.>
Go to step 7.
VDC (Diagnostics)
No
Repair or replace
open circuit
between VDCCM
and ECM.
Repair or replace
ground short cir-
cuit between
VDCCM and
ECM.
Repair or replace
battery short cir-
cuit between
VDCCM and
ECM.
Go to step 5.
Repair or replace
ECM connector.
Replace VDCCM.
<Ref. to VDC-9,
VDC Control Mod-
ule (VDCCM).>