Subaru Legacy IV (2008 year). Manual - part 908

ABS(diag)-31

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

12.Diagnostic Procedure with Diagnostic Trouble Code (DTC)

A: DTC C0101 ABS WHEEL SPEED SENSOR MALFUNCTION RR SENSOR 

(BROKEN WIRE, INPUT VOLTAGE TOO HIGH)

NOTE:
Refer to DTC C0104 for diagnostic procedure. <Ref. to ABS(diag)-32, DTC C0104 ABS WHEEL SPEED
SENSOR MALFUNCTION FL SENSOR (BROKEN WIRE, INPUT VOLTAGE TOO HIGH), Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>

B: DTC C0102 ABS WHEEL SPEED SENSOR MALFUNCTION RL SENSOR 

(BROKEN WIRE, INPUT VOLTAGE TOO HIGH)

NOTE:
Refer to DTC C0104 for diagnostic procedure. <Ref. to ABS(diag)-32, DTC C0104 ABS WHEEL SPEED
SENSOR MALFUNCTION FL SENSOR (BROKEN WIRE, INPUT VOLTAGE TOO HIGH), Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>

C: DTC C0103 ABS WHEEL SPEED SENSOR MALFUNCTION FR SENSOR 

(BROKEN WIRE, INPUT VOLTAGE TOO HIGH)

NOTE:
Refer to DTC C0104 for diagnostic procedure. <Ref. to ABS(diag)-32, DTC C0104 ABS WHEEL SPEED
SENSOR MALFUNCTION FL SENSOR (BROKEN WIRE, INPUT VOLTAGE TOO HIGH), Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>

ABS(diag)-32

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

D: DTC C0104 ABS WHEEL SPEED SENSOR MALFUNCTION FL SENSOR 

(BROKEN WIRE, INPUT VOLTAGE TOO HIGH)

DTC DETECTING CONDITION:
• Defective ABS wheel speed sensor (broken wire, input voltage too high)
• Defective harness connector
TROUBLE SYMPTOM:
ABS does not operate.
WIRING DIAGRAM:

4

3

1

16

17

2

15

B98

R72

R2

E

1

2

15

14

6

5

R73

1

2

B6

B15

R73

R72

1

2

1 2

2 1

6

5

B301

2

1

B15

B6

B301

B98

1 2 3 4 5 6 7 8 9 10 11

16 17 18 19 20 21 22 23 24 25 26

13

12

15

14

ABSCM & H/U

ABS00995

1 2 3

4 5 6 7

8 9 10 11 12 13 14 15 16

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

FRONT ABS

WHEEL SPEED 

SENSOR LH

FRONT ABS

WHEEL SPEED 

SENSOR RH

REAR ABS

WHEEL SPEED 

SENSOR LH

REAR ABS

WHEEL SPEED 

SENSOR RH

ABS(diag)-33

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK POOR CONTACT IN CONNECTOR.
Check if there is poor contact between 
ABSCM&H/U and ABS wheel speed sensor.

Is there poor contact?

Repair the connec-
tor.

Go to step 2.

2

CHECK HARNESS CONNECTOR BETWEEN 
ABSCM&H/U AND ABS WHEEL SPEED 
SENSOR.
1) Disconnect the connector (B301) from the 
ABSCM&H/U.
2) Disconnect the connector from the ABS 
wheel speed sensor.
3) Measure the resistance between 
ABSCM&H/U connector and ABS wheel speed 
sensor connector.

Connector & terminal
DTC C0101

(B301) No. 3 — (R72) No. 1:
(B301) No. 4 — (R72) No. 2:

DTC C0102

(B301) No. 2 — (R73) No. 1:
(B301) No. 17 — (R73) No. 2:

DTC C0103

(B301) No. 5 — (B6) No. 2:
(B301) No. 6 — (B6) No. 1:

DTC C0104

(B301) No. 16 — (B15) No. 2:
(B301) No. 1 — (B15) No. 1:

Is the resistance less than 0.5 

:? Go to step 3.

Repair the harness 
connector between 
ABSCM&H/U and 
ABS wheel speed 
sensor.

3

CHECK GROUND SHORT OF HARNESS.
Measure the resistance between the 
ABSCM&H/U connector and chassis ground.

Connector & terminal
DTC C0101

(B301) No. 4 — Chassis ground:

DTC C0102

(B301) No. 17 — Chassis ground:

DTC C0103

(B301) No. 6 — Chassis ground:

DTC C0104

(B301) No. 1 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 4.

Repair the harness 
connector between 
ABSCM&H/U and 
ABS wheel speed 
sensor.

4

CHECK ABS WHEEL SPEED SENSOR POW-
ER SUPPLY CIRCUIT.
1) Connect ABSCM&H/U connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between ABS wheel 
speed sensor connector and chassis ground.

Connector & terminal
DTC C0101

(R72) No. 1 (+) — Chassis ground (–):

DTC C0102

(R73) No. 1 (+) — Chassis ground (–):

DTC C0103

(B6) No. 2 (+) — Chassis ground (–):

DTC C0104

(B15) No. 2 (+) — Chassis ground (–):

Is the voltage 5 — 16 V?

Go to step 6.

Go to step 5.

ABS(diag)-34

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ABS (DIAGNOSTICS)

E: DTC C0105 REAR ABS WHEEL SPEED SENSOR RH MALFUNCTION (ABS 

WHEEL SPEED SENSOR ABNORMAL SIGNAL)

NOTE:
Refer to DTC C0108 for diagnostic procedure. <Ref. to ABS(diag)-35, DTC C0108 FRONT ABS WHEEL
SPEED SENSOR LH MALFUNCTION (ABS WHEEL SPEED SENSOR ABNORMAL SIGNAL), Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>

F: DTC C0106 REAR ABS WHEEL SPEED SENSOR LH MALFUNCTION (ABS 

WHEEL SPEED SENSOR ABNORMAL SIGNAL)

NOTE:
Refer to DTC C0108 for diagnostic procedure. <Ref. to ABS(diag)-35, DTC C0108 FRONT ABS WHEEL
SPEED SENSOR LH MALFUNCTION (ABS WHEEL SPEED SENSOR ABNORMAL SIGNAL), Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>

G: DTC C0107 FRONT ABS WHEEL SPEED SENSOR RH MALFUNCTION (ABS 

WHEEL SPEED SENSOR ABNORMAL SIGNAL)

NOTE:
Refer to DTC C0108 for diagnostic procedure. <Ref. to ABS(diag)-35, DTC C0108 FRONT ABS WHEEL
SPEED SENSOR LH MALFUNCTION (ABS WHEEL SPEED SENSOR ABNORMAL SIGNAL), Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>

5

CHECK THE ABSCM&H/U POWER SUPPLY 
CIRCUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the ABSCM&H/U connectors.
3) Turn the ignition switch to ON.
4) Measure the voltage between ABSCM&H/U 
connector and chassis ground.

Connector & terminal

(B301) No. 18 (+) — (B301) No. 15 (–):

Is the voltage 10 — 15 V?

Go to step 6.

Check the genera-
tor, battery and 
ABSCM&H/U
power supply cir-
cuit.

6

CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Install the ABS wheel speed sensor.
2) Prepare an oscilloscope.
3) Check the ABS wheel speed sensor. <Ref. 
to ABS-14, ABS WHEEL SPEED SENSOR, 
INSPECTION, Front ABS Wheel Speed Sen-
sor.>

Is the pattern the same wave-
form as shown in the figure?

Go to step 7.

Replace the ABS 
wheel speed sen-
sor.

7

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 8.

8

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).>

It results from a 
temporary noise 
interference.

Step

Check

Yes

No