Subaru Legacy IV (2008 year). Manual - part 912

ABS(diag)-47

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

S: DTC C0109 POWER VOLTAGE MALFUNCTION

DTC DETECTING CONDITION:
Power supply voltage of the ABSCM&H/U is too low or too high.
TROUBLE SYMPTOM:
• ABS does not operate.
• EBD may not operate.

NOTE:
If EBD does not operate, the brake warning light illuminates in addition to ABS warning light. Both warning
lights go off if voltage returns.
WIRING DIAGRAM:

ABS00805

MAIN SBF

SBF-6

No.33

B301

ABSCM & H/U

BATTERY

GENERATOR

IGNITION
SWITCH

B301

1 2 3 4 5 6 7 8 9 10 11

16 17 18 19 20 21 22 23 24 25 26

ABS(diag)-48

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

Step

Check

Yes

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.

CHECK BATTERY TERMINAL.
Turn the ignition switch to OFF.

Are the positive and negative
battery terminals tightened
securely?

Go to step 3.

Tighten the termi-
nal.

CHECK INPUT VOLTAGE OF ABSCM&H/U.
1) Disconnect the ABSCM&H/U connectors.
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 ABSCM&H/U
connector and chassis ground.

Connector & terminal

(B301) No. 18 (+) — Chassis ground (–):

Is the voltage 10 — 15 V?

Go to step 4.

Repair the
ABSCM&H/U
power circuit.

CHECK THE ABSCM&H/U GROUND CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance between the
ABSCM&H/U connector and chassis ground.

Connector & terminal

(B301) No. 15 — Chassis ground:

Is the resistance less than 0.5

:? Go to step 5.

Repair the
ABSCM&H/U
ground harness.

CHECK POOR CONTACT IN CONNECTOR.

Is there poor contact in connec-
tor between generator, battery
and ABSCM&H/U?

Repair the connec-
tor.

Go to step 6.

CHECK ABSCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to ABS(diag)-20,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
ABS(diag)-19, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
ABSCM only. <Ref.
to ABS-8,
REPLACEMENT,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>

Go to step 7.

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
ABS(diag)-29, List
of Diagnostic Trou-
ble Code (DTC).>

Temporary poor
contact occurs.

ABS(diag)-49

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

T: DTC C0140 CAN COMMUNICATION MALFUNCTION

DTC DETECTING CONDITION:
Defective CAN communication
TROUBLE SYMPTOM:
Possibly the vehicle speed cannot output on CAN.

Step

Check

Yes

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?

Repair it according
to DTC of LAN sys-
tem.

Replace the
ABSCM only. <Ref.
to ABS-8,
REPLACEMENT,
ABS Control Mod-
ule and Hydraulic
Control Unit
(ABSCM&H/U).>

ABS(diag)-50

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

U: DTC C0114 VALVE RELAY MALFUNCTION

DTC DETECTING CONDITION:
Defective valve relay
TROUBLE SYMPTOM:
• ABS does not operate.
• EBD does not operate depending on the trouble contents.

NOTE:
Brake warning light illuminates as well as ABS warning light when EBD does not operate.
WIRING DIAGRAM:

B301

ABSCM & H/U

INLET

MAIN SBF

SBF-6

No.1

No.33

INLET

FL OUTLET

FR OUTLET

RL OUTLET

RR OUTLET

4 5 6 7 8 9

16 17 18 19 20

2 3

21 22 23 24 25 26

10 11

ABS00996

BATTERY

IGNITION
SWITCH

OR RELA

VALVE RELAY

SOLENOID V

PUMP MOTOR

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