Subaru Legacy IV (2008 year). Service manual — part 926

VDC(diag)-19

Subaru Select Monitor

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

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 11 V or more?

Go to step 3.

Charge or replace
the battery.

3

CHECK BATTERY TERMINAL.

Is there poor contact at the bat-
tery 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 systems can
be executed normally.

Is the system name displayed
on Subaru 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 sys-
tems can be executed normally.

Is the system name displayed
on Subaru Select Monitor?

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
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. 7 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 7.

Repair the harness
and connector
between each con-
trol module and
data link connec-
tor.

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. 7 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 8.

Repair the harness
and connector
between each con-
trol module and
data link connec-
tor.

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. 7 — (B40) No. 7:

Is the resistance less than 0.5

:? Go to step 9.

Repair harness
and connector
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 VDCCM&H/
U connector into
VDCCM&H/U.

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. 28 (+) — Chassis ground (–):

Is the voltage 10 — 15 V?

Go to step 11.

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

VDC(diag)-20

Subaru Select Monitor

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

11

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

Connector & terminal

(B310) No. 25 — Chassis ground:

Is the resistance less than 0.5

:? Go to step 12.

Repair the open
circuit of
VDCCM&H/U
ground harness
and poor contact of
connector.

12

CHECK POOR CONTACT IN CONNECTOR.

Is there poor contact in control
module power supply, ground
circuit and data link connector?

Repair the connec-
tor.

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Step

Check

Yes

No

VDC(diag)-21

Read Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

7. Read Diagnostic Trouble

Code (DTC)

A: OPERATION

1) On the «Main Menu» display, select the {Each
System Check}.
2) On the «System Selection Menu» display, select
the {Brake Control System}.
3) Click the [OK] button after the {VDC} is dis-
played.
4) On the «Brake Control Diagnosis» display, se-
lect the {Diagnostic Code(s) Display}.
5) Record the DTC and data.

NOTE:
• For detailed operation procedure, refer to the
“PC application help for Subaru Select Monitor”.
• For details concerning DTCs, refer to “List of Di-
agnostic Trouble Code (DTC)”. <Ref. to VDC(di-
ag)-34, List of Diagnostic Trouble Code (DTC).>
• Up to 3 DTCs are displayed in the order of detec-
tion.
• If a particular DTC is not stored in memory prop-
erly at the occurrence of problem (due to a drop in
VDCCM&H/U power supply etc.), the DTC suffixed
with a question mark “?” is displayed on Subaru Se-
lect Monitor display screen. This shows it may be
an unreliable reading.

Display

Contents to be displayed

(Current)

The current DTC is displayed on Subaru
Select Monitor display screen.

(Old)

The latest DTC in previous troubles is
displayed on Subaru Select Monitor dis-
play screen.

(Older)

The second latest DTC in previous trou-
bles is displayed on Subaru Select Moni-
tor display screen.

(Before 3)

The third latest DTC in previous troubles
is displayed on Subaru Select Monitor
display screen.

VDC(diag)-22

Inspection Mode

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

8. Inspection Mode

A: PROCEDURE

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

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