Subaru Legacy III (2000-2003 year). Manual - part 792

VDC-204

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

7

CHECK POWER SUPPLY FOR VALVE RE-
LAY.
1) Disconnect connector (F89) from relay box.
2) Turn ignition switch to ON.
3) Measure voltage between relay box con-

nector and chassis ground.

Connector & terminal

(F89) No. 1 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified 
range?

10 — 15 V

Go to step 8.

Repair harness 
between battery 
and relay box con-
nector. Check fuse 
No. 8.

8

CHECK OPEN CIRCUIT AND GROUND 
SHORT IN POWER SUPPLY CIRCUIT OF 
RELAY BOX.
1) Disconnect connector (VDC1) from VDCH/

U.

2) Connect connector (F89) to relay box.
3) Turn ignition switch to ON.
4) Measure voltage of relay box.

Connector & terminal

(VDC6) No. 87 (

++++

) — Chassis ground (

−−−−

):

Is the measured value within the specified 
range?

10 — 15 V

Go to step 9.

Replace relay box 
and check fuse 
No. 8.

9

CHECK OPEN CIRCUIT IN CONTROL CIR-
CUIT OF RELAY BOX.
1) Turn ignition switch to OFF.
2) Disconnect connector (F90) from relay box.
3) Measure resistance between relay box con-

nector and valve relay installing point.

Connector & terminal

(VDC4) No. 5 — (VDC6) No. 85:
(VDC4) No. 1 — (VDC6) No. 86:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 10.

Replace relay box.

10

CHECK GROUND SHORT IN CONTACT 
POINT CIRCUIT OF RELAY BOX.
Measure resistance between relay box con-
nector and chassis ground.

Connector & terminal

(VDC4) No. 5 — Chassis ground:
(VDC4) No. 1 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 11.

Replace relay box 
and check fuse 
SBF6.

11

CHECK OPEN CIRCUIT IN CONTROL SYS-
TEM HARNESS OF VALVE RELAY.
1) Turn ignition switch to OFF.
2) Disconnect connector from VDCCM.
3) Measure resistance between VDCCM con-

nector and relay box connector.

Connector & terminal

(F87) No. 47 — (F90) No. 5:
(F87) No. 27 — (F90) No. 1:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 12.

Repair harness 
between VDCCM 
and relay box.

Step

Value

Yes

No

VDC-205

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

12

CHECK GROUND SHORT IN CONTROL 
SYSTEM HARNESS OF VALVE RELAY.
Measure resistance between VDCCM connec-
tor and chassis ground.

Connector & terminal

(F87) No. 47 — Chassis ground:
(F87) No. 27 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 13.

Repair harness 
between VDCCM 
and relay box.

13

CHECK OPEN CIRCUIT IN CONTACT POINT 
CIRCUIT OF RELAY BOX.
Measure resistance between VDCH/U connec-
tor and valve relay installing point.

Connector & terminal

(VDC1) No. 2 — (VDC6) No. 30:

Is the measured value less than the specified 
value?

0.5 

Ω

Go to step 14.

Replace relay box.

14

CHECK GROUND SHORT IN CONTACT 
POINT CIRCUIT OF RELAY BOX.
Measure resistance between VDCH/U connec-
tor and chassis ground.

Connector & terminal

(VDC1) No. 2 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 15.

Replace relay box 
and check fuse 
No. 8.

15

CHECK RESISTANCE OF INLET AND CUT 
SOLENOID VALVES.
1) Disconnect connector from VDCH/U.
2) Measure resistance between VDCH/U con-

nector terminals.

Connector & terminal

(VDC5) No. 8 — (VDC2) No. 2:
(VDC5) No. 5 — (VDC2) No. 2:
(VDC5) No. 6 — (VDC2) No. 2:
(VDC5) No. 7 — (VDC2) No. 2:
(VDC5) No. 9 — (VDC2) No. 2:
(VDC5) No. 12 — (VDC2) No. 2:

Is the measured value within the specified 
range?

8.04 — 9.04 

Ω

Go to step 16.

Replace VDCH/U.  
<Ref. to VDC-8, 
VDC Control Mod-
ule (VDCCM).>

16

CHECK RESISTANCE OF OUTLET SOLE-
NOID VALVE.
Measure resistance between VDCH/U connec-
tor terminals.

Connector & terminal

(VDC5) No. 4 — (VDC2) No. 2:
(VDC5) No. 1 — (VDC2) No. 2:
(VDC5) No. 2 — (VDC2) No. 2:
(VDC5) No. 3 — (VDC2) No. 2:
(VDC5) No. 10 — (VDC2) No. 2:
(VDC5) No. 11 — (VDC2) No. 2:

Is the measured value within the specified 
range?

4.04 — 4.54 

Ω

Go to step 17.

Replace VDCH/U.  
<Ref. to VDC-8, 
VDC Control Mod-
ule (VDCCM).>

Step

Value

Yes

No

VDC-206

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

17

CHECK GROUND SHORT OF SOLENOID 
VALVE.
Measure resistance between VDCH/U connec-
tor and chassis ground.

Connector & terminal

(VDC2) No. 2 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 18.

Replace VDCH/U 
and check all 
fuses.  <Ref. to 
VDC-8, VDC Con-
trol Module 
(VDCCM).>

18

CHECK GROUND SHORT OF HARNESS.
1) Turn ignition switch to OFF.
2) Measure resistance between VDCCM con-

nector and chassis ground.

Connector & terminal

(F87) No. 30 — Chassis ground:
(F87) No. 24 — Chassis ground:
(F87) No. 23 — Chassis ground:
(F87) No. 31 — Chassis ground:
(F87) No. 26 — Chassis ground:
(F87) No. 25 — Chassis ground:
(F87) No. 3 — Chassis ground:
(F87) No. 51 — Chassis ground:
(F87) No. 50 — Chassis ground:
(F87) No. 4 — Chassis ground:
(F87) No. 2 — Chassis ground:
(F87) No. 29 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 19.

Repair harness 
between VDCH/U 
and VDCCM.

19

CHECK HARNESS/CONNECTOR BETWEEN 
VDCCM AND VDCH/U.
1) Connect connector (F91) to VDCH/U.
2) Measure resistance between VDCCM con-

nector and VDCH/U

Connector & terminal

(F87) No. 30 — (VDC2) No. 2:
(F87) No. 24 — (VDC2) No. 2:
(F87) No. 23 — (VDC2) No. 2:
(F87) No. 31 — (VDC2) No. 2:
(F87) No. 26 — (VDC2) No. 2:
(F87) No. 25 — (VDC2) No. 2:

Is the measured value within the specified 
range?

8.0 — 10.0 

Ω

Go to step 20.

Repair harness/
connector 
between VDCH/U 
and VDCCM.

20

CHECK HARNESS/CONNECTOR BETWEEN 
VDCCM AND VDCH/U.
Measure resistance between VDCCM connec-
tor terminals.

Connector & terminal

(F87) No. 3 — (VDC2) No. 2:
(F87) No. 51 — (VDC2) No. 2:
(F87) No. 50 — (VDC2) No. 2:
(F87) No. 4 — (VDC2) No. 2:
(F87) No. 2 — (VDC2) No. 2:
(F87) No. 29 — (VDC2) No. 2:

Is the measured value within the specified 
range?

4.0 — 6.0 

Ω

Go to step 21.

Repair harness/
connector 
between VDCH/U 
and VDCCM.

21

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connector between 
VDCCM and VDCH/U?

There is poor contact.

Repair connector.

Go to step 22.

Step

Value

Yes

No

VDC-207

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

22

CHECK VDCCM.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the diagnostic trouble code.

Is the same diagnostic trouble code as in 
the current diagnosis still being output?

Same DTC indicated.

Replace VDCCM.  
<Ref. to VDC-8, 
VDC Control Mod-
ule (VDCCM).>

Go to step 23.

23

CHECK ANY OTHER DIAGNOSTIC TROU-
BLE CODES APPEARANCE.
Are other diagnostic trouble codes being out-
put?

Other DTC indicated.

Proceed with the 
diagnosis corre-
sponding to the 
diagnostic trouble 
code.

A temporary poor 
contact.

Step

Value

Yes

No