Subaru Legacy IV (2008 year). Manual — part 935

VDC(diag)-55

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Y: DTC C0042 POWER SUPPLY VOLTAGE FAILURE

DTC DETECTING CONDITION:
Improper VDCCM&H/U power supply voltage
TROUBLE SYMPTOM:
• ABS does not operate.
• EBD may not operate.
• VDC does not operate.

NOTE:
Warning lights go off if voltage returns.
WIRING DIAGRAM:

MAIN SBF

SBF-6

No.33

B310

E

E

25

28

VDCCM & H/U

BATTERY

GENERATOR

IGNITION
SWITCH

B310

4 5 6 7 8 9

26 27 28 29 30

2 3

1

31 32 33 34 35 36

10 11

14 15 16 17 18 19

37 38 39 40

12 13

41 42 43 44 45 46

20 21

23

24

22

25

VDC00463

VDC(diag)-56

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK GENERATOR.
1) Start the engine.
2) Run the engine at idle after warming up.
3) Measure the voltage between generator ter-
minal B and chassis ground.

Terminals

Generator B terminal (+) — Chassis
ground (–):

Is the voltage 10 — 15 V?

Go to step 2.

Repair the genera-
tor.

2

CHECK BATTERY TERMINAL.
Turn the ignition switch to OFF.

Are the positive and negative
battery terminals clamped
tightly?

Go to step 3.

Tighten the termi-
nal.

3

CHECK VDCCM&H/U INPUT VOLTAGE.
1) Disconnect the connector from the
VDCCM&H/U.
2) Run the engine at idle.
3) Operate devices such as headlights, air
conditioner, defogger, etc. which produce an
electrical load.
4) Measure the 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 4.

Repair the power
supply circuit.

4

CHECK VDCCM&H/U GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance 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 5.

Repair the
VDCCM&H/U
ground harness.

5

CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in connec-

tor between generator, battery
and VDCCM&H/U?

Repair the connec-
tor.

Go to step 6.

6

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

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

Go to step 7.

7

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

Temporary poor
contact occurs.

VDC(diag)-57

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Z: DTC C0044 TCM COMMUNICATION CIRCUIT

DTC DETECTING CONDITION:
No CAN signal from TCM.
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.

Step

Check

Yes

No

1

CHECK LAN SYSTEM.
Perform the diagnosis for LAN system. <Ref. to
LAN(diag)-27, OPERATION, Read Diagnostic
Trouble Code (DTC).>

Is there any fault in LAN sys-
tem?

Perform the diag-
nosis according to
DTC for LAN sys-
tem.

Go to step 2.

2

CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in TCM

connector?

Repair the connec-
tor.

Go to step 3.

3

CHECK TCM.

Is the TCM normal?

Go to step 4.

Replace the TCM.
<Ref. to 4AT-61,
Transmission Con-
trol Module
(TCM).> <Ref. to
5AT-60, Transmis-
sion Control Mod-
ule (TCM).>

4

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.

Go to step 5.

5

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.

VDC(diag)-58

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

AA:DTC C0045 INCORRECT VDC CONTROL MODULE SPECIFICATIONS

DTC DETECTING CONDITION:
Different control module specification
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.

NOTE:
When parameter selection for VDCCM is improper, this DTC may be memorized.

Step

Check

Yes

No

1

CHECK VDCCM REPLACEMENT HISTORY. Is there replacement history of

VDCCM alone?

Go to step 2.

Go to step 3.

2

CHECK VDCCM IDENTIFICATION NUMBER.
Check the identification number on the sticker
attached on the VDCCM side.
AT:

T3 (2.5 L turbo models and OUTBACK 3.0 L
models)
T7 (Sedan 3.0L with 18 inch tire model)
TA (2.5L non-turbo model and sedan 3.0L
with 17 inch tire model)

MT:

T4 (2.5L turbo model)
TB (2.5L non-turbo model)

Is the identification number cor-
rect?

Go to step 4.

Replace the
VDCCM only.

3

CHECK VDCCM&H/U IDENTIFICATION
NUMBER.
Check the identification number stamped on the
upper side of the H/U.
AT:

T3 (2.5 L turbo models and OUTBACK 3.0 L
models)
T7 (Sedan 3.0L with 18 inch tire model)
TA (2.5L non-turbo model and sedan 3.0L
with 17 inch tire model)

MT:

T4 (2.5L turbo model)
TB (2.5L non-turbo model)

Is the identification number cor-
rect?

Go to step 4.

Replace the
VDCCM&H/U.

4

CHECK PARAMETER SELECTED FOR VDC-
CM.
<Ref. to VDC(diag)-17, PARAMETER CHECK,
OPERATION, Subaru Select Monitor.>

Does the parameter registered
to the VDCCM match with the
target vehicle?

Go to step 5.

Select and register
the correct param-
eter. <Ref. to
VDC(diag)-16,
PARAMETER
SELECTION,
OPERATION, Sub-
aru Select Moni-
tor.>

5

CHECK TCM SPECIFICATION.
Check the TCM specification.

Is the specification of TCM
same as vehicle specification?

Go to step 6.

Replace the TCM.
<Ref. to 4AT-61,
Transmission Con-
trol Module
(TCM).> <Ref. to
5AT-60, Transmis-
sion Control Mod-
ule (TCM).>

6

CHECK AT SYSTEM.
1) Start the engine.
2) Check the DTC in AT system.

Is DTC of AT system displayed? Repair the AT sys-

tem.

Go to step 7.