Subaru Legacy III (2000-2003 year). Manual - part 729

ABS-134

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SUBARU SELECT MONITOR

AE:DTC 56 OPEN OR SHORT CIRCUIT IN G SENSOR CIRCUIT

DIAGNOSIS:
• Faulty G sensor output voltage
TROUBLE SYMPTOM:
• ABS does not operate.
WIRING DIAGRAM:

ABS00312

F55

R70

F62

ABS CONTROL MODULE AND 
HYDRAULIC  CONTROL UNIT

ABS

G SENSOR

F49

2

1

3

F49

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22

27 28 29 30 31

23

24

25

26

3

7

6

28

1

2

3

F55

R49

R70

2

8

30

1

2 3

4 5 6 7 8

ABS-135

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SUBARU SELECT MONITOR

Step

Value

Yes

No

1

CHECK OUTPUT OF G SENSOR USING SE-
LECT MONITOR.
1) Select “Current data display & Save” on the 

select monitor.

2) Read the G sensor output in select monitor 

data display.
Is the G sensor output on the monitor dis-
play within the specified range  when the G 
sensor is in horizontal position?

2.1 - 2.5 V

Go to step 2.

Go to step 5.

2

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connector between 
ABSCM&H/U and G sensor?

There is no poor contact.

Go to step 3.

Repair connector.

3

CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the DTC.

Is the same DTC still being output?

Same DTC is not indicated.

Go to step 4.

Replace 
ABSCM&H/U.  
<Ref. to ABS-6, 
ABS Control Mod-
ule and Hydraulic 
Control Unit 
(ABSCM&H/U).> 

4

CHECK ANY OTHER DTC APPEARANCE.
Are other DTC being output?

Other DTC is not indicated.

A temporary poor 
contact.

Proceed with the 
diagnosis corre-
sponding to the 
DTC.

5

CHECK INPUT VOLTAGE OF G SENSOR.
1) Turn ignition switch to OFF.
2) Remove console box.
3) Disconnect G sensor from body. (Do not 

disconnect connector.)

4) Turn ignition switch to ON.
5) Measure voltage between G sensor con-

nector terminals.

Connector & terminal

(R70) No. 1 (+) — No. 3 (

−−−−

):

Is the measured value within the specified 
range?

4.75 - 5.25 V

Go to step 6.

Repair harness/
connector 
between G sensor 
and ABSCM&H/U.

6

CHECK OPEN CIRCUIT IN G SENSOR OUT-
PUT HARNESS AND GROUND HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM&H/U.
3) Measure resistance between ABSCM&H/U 

connector terminals.

Connector & terminal

(F49) No. 6 — No. 28:

Is the measured value within the specified 
range?

5.0 - 5.6 k

Ω

Go to step 7.

Repair harness/
connector 
between G sensor 
and ABSCM&H/U.

7

CHECK GROUND SHORT IN G SENSOR 
OUTPUT HARNESS.
1) Disconnect connector from G sensor.
2) Measure resistance between ABSCM&H/U 

connector and chassis ground.

Connector & terminal

(F49) No. 6 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 8.

Repair harness 
between G sensor 
and ABSCM&H/U.

ABS-136

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SUBARU SELECT MONITOR

8

CHECK G SENSOR.
1) Connect connector to G sensor.
2) Connect connector to ABSCM&H/U.
3) Turn ignition switch to ON.
4) Measure voltage between G sensor con-

nector terminals.

Connector & terminal

(R70) No. 2 (+) — No. 3 (

−−−−

):

Is the voltage between within the specified 
range  when G sensor is horizontal?

2.1 - 2.5 V

Go to step 9.

Replace G sen-
sor.  <Ref. to ABS-
21, G Sensor.>

9

CHECK G SENSOR.
Measure voltage between G sensor connector 
terminals.

Connector & terminal

(R70) No. 2 (+) — No. 3 (

−−−−

):

Is the voltage between within the specified 
range  when G sensor is inclined forwards to 
90

°

?

3.7 - 4.1 V

Go to step 10.

Replace G sen-
sor.  <Ref. to ABS-
21, G Sensor.> 

10

CHECK G SENSOR.
Measure voltage between G sensor connector 
terminals.

Connector & terminal

(R70) No. 2 (+) — No. 3 (

−−−−

):

Is the voltage between within the specified 
range  when G sensor is inclined backwards to 
90

°

?

0.5 - 0.9 V

Go to step 11.

Replace G sen-
sor.  <Ref. to ABS-
21, G SENSOR, .> 

11

CHECK POOR CONTACT IN CONNECTORS.
Turn ignition switch to OFF.
Is there poor contact in connector between 
ABSCM&H/U and G sensor?

There is no poor contact.

Go to step 12.

Repair connector.

12

CHECK ABSCM&H/U.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the DTC.

Is the same DTC still being output?

Same DTC is not indicated.

Go to step 13.

Replace 
ABSCM&H/U.  
<Ref. to ABS-6, 
ABS Control Mod-
ule and Hydraulic 
Control Unit 
(ABSCM&H/U).> 

13

CHECK ANY OTHER DTC APPEARANCE.
Are other DTC being output?

Other DTC is not indicated.

A temporary poor 
contact.

Proceed with the 
diagnosis corre-
sponding to the 
DTC.

Step

Value

Yes

No

ABS-137

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SUBARU SELECT MONITOR

MEMO: