Subaru Legacy (2005 year). Manual - part 789

VDC(diag)-21

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Subaru Select Monitor

Step

Check

Yes

No

1

CHECK IGNITION SWITCH.

Is the ignition switch ON?

Go to step 2.

Turn the ignition 
switch to ON, and 
select VDC mode 
using Subaru 
Select Monitor.

2

CHECK BATTERY.
1) Turn the ignition switch to OFF.
2) Measure the battery voltage.

Is the voltage more than 11 V? Go to step 3.

Charge or replace 
the battery.

3

CHECK BATTERY TERMINAL.

Is there poor contact at battery 
terminal?

Repair or tighten 
the battery termi-
nal.

Go to step 4.

4

CHECK SUBARU SELECT MONITOR COM-
MUNICATION.
1) Turn the ignition switch to ON.
2) Using the Subaru Select Monitor, check 
whether communication to other system can 
be executed normally.

Are the system name and 
model year displayed on Sub-
aru Select Monitor?

Go to step 8.

Go to step 5.

5

CHECK SUBARU SELECT MONITOR COM-
MUNICATION.
1) Turn the ignition switch to OFF.
2) Disconnect the VDCCM&H/U connector.
3) Turn the ignition switch to ON.
4) Check whether communication to other 
systems can be executed normally.

Are the system name and 
model year displayed on Sub-
aru Select Monitor?

Replace the 
VDCCM&H/U. 
<Ref. to VDC-7, 
VDC Control Mod-
ule and Hydraulic 
Control Unit 
(VDCCM&H/U).>

Go to step 6.

6

CHECK HARNESS CONNECTOR BETWEEN 
EACH CONTROL MODULE AND DATA LINK 
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the VDCCM&H/U, ECM and 
TCM.
3) Measure the resistance between data link 
connector and chassis ground.

Connector & terminal

(B40) No. 10 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 7.

Repair the har-
ness and connec-
tor between each 
control module 
and data link con-
nector.

7

CHECK OUTPUT SIGNAL FOR VDCCM&H/
U.
1) Turn the ignition switch to ON.
2) Measure the voltage between data link con-
nector and chassis ground.

Connector & terminal

(B40) No. 10 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Go to step 8.

Repair the har-
ness and connec-
tor between each 
control module 
and data link con-
nector.

8

CHECK HARNESS CONNECTOR BETWEEN 
VDCCM&H/U AND DATA LINK CONNEC-
TOR.
Measure the resistance between VDCCM&H/U 
connector and data link connector.

Connector & terminal

(B310) No. 26 — (B40) No. 10:

Is the resistance less than 0.5 
Ω?

Go to step 9.

Repair the har-
ness and connec-
tor between 
VDCCM&H/U and 
data link connec-
tor.

9

CHECK INSTALLATION OF VDCCM&H/U 
CONNECTOR.
Turn the ignition switch to OFF.

Is the VDCCM&H/U connector 
inserted into VDCCM&H/U 
until the clamp locks onto it?

Go to step 10.

Insert the 
VDCCM&H/U con-
nector into 
VDCCM&H/U.

VDC(diag)-22

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Subaru Select Monitor

10

CHECK POWER SUPPLY CIRCUIT.
1) Turn the ignition switch to ON. (engine 
OFF)
2) Measure the ignition power supply voltage 
between VDCCM&H/U connector and chassis 
ground.

Connector & terminal

(B310) No. 14 (+) — Chassis ground (

−

):

Is the voltage 10 — 15 V?

Go to step 11.

Repair open circuit 
in harness 
between 
VDCCM&H/U and 
battery.

11

CHECK HARNESS CONNECTOR BETWEEN 
VDCCM&H/U AND CHASSIS GROUND.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from VDCCM&H/
U.
3) Measure the resistance of harness 
between VDCCM&H/U connector and chassis 
ground.

Connector & terminal

(B310) No. 6 — Chassis ground:

Is the resistance less than 0.5 
Ω?

Go to step 12.

Repair open circuit 
in harness 
between 
VDCCM&H/U and 
inhibitor side con-
nector, and poor 
contact in cou-
pling connector.

12

CHECK POOR CONTACT IN CONNECTOR. Is there poor contact in control 

module power supply, ground 
circuit and data link connector?

Repair the con-
nector.

Replace the 
VDCCM&H/U. 
<Ref. to VDC-7, 
VDC Control Mod-
ule and Hydraulic 
Control Unit 
(VDCCM&H/U).>

Step

Check

Yes

No

VDC(diag)-23

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Read Diagnostic Trouble Code (DTC)

7. Read Diagnostic Trouble 

Code (DTC)

A: OPERATION

For details concerning DTC reading procedure, re-
fer to “Subaru Select Monitor”. <Ref. to VDC(diag)-
16, Subaru Select Monitor.>

VDC(diag)-24

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Inspection Mode

8. Inspection Mode

A: PROCEDURE

Reproduce the malfunction occurrence condition
as possible.
Drive the vehicle at least ten minutes.

NOTE:
Make sure the vehicle is not dragged to one side
under usual driving condition.