Subaru Legacy III (2000-2003 year). Manual - part 711

ABS-62

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

U: DTC 41 ABNORMAL ABS CONTROL MODULE

DIAGNOSIS:
• Faulty ABSCM&H/U.
TROUBLE SYMPTOM:
• ABS does not operate.
WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK GROUND CIRCUIT OF ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Disconnect connector from ABSCM&H/U.
3) Measure resistance between ABSCM&H/U 

and chassis ground.

Connector & terminal

(F49) No. 23 — Chassis ground:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 2.

Repair 
ABSCM&H/U 
ground harness.

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

F49

23

ABS CONTROL MODULE AND 

HYDRAULIC CONTROL UNIT

F49

ABS00295

ABS-63

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

2

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connectors between 
battery, ignition switch and ABSCM&H/U? 

There is no poor contact.

Go to step 3.

Repair connector.

3

CHECK SOURCES OF SIGNAL NOISE.
Is the car telephone or the wireless transmitter 
properly installed?

Installed properly

Go to step 4.

Properly install the 
car telephone or 
the wireless trans-
mitter.

4

CHECK SOURCES OF SIGNAL NOISE.
Are noise sources (such as an antenna) 
installed near the sensor harness?

Noise source is not installed 
near the sensor harness.

Go to step 5.

Install the noise 
sources apart from 
the sensor har-
ness.

5

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 as in the current diagno-
sis still being output?

Same DTC is not indicated.

Go to step 6.

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

6

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-64

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

V: DTC 42 SOURCE VOLTAGE IS ABNORMAL.

DIAGNOSIS:
• Power source voltage of the ABSCM&H/U is low or high.
TROUBLE SYMPTOM:
• ABS does not operate.
WIRING DIAGRAM:

ABS00294

1

23

ABS CONTROL MODULE AND HYDRAULIC CONTROL UNIT

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

F49

BATTERY

NO

. 18 15A

SBF-4 50A

SBF-1 100A

GENERATOR

IGNITION 
SWITCH

ABS-65

ABS (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

Step

Value

Yes

No

1

CHECK GENERATOR.
1) Start engine.
2) Idling after warm-up.
3) Measure voltage between generator B ter-

minal and chassis ground.

Terminal

Generator B terminal — Chassis 
ground:

Is the measured value within the specified 
range?

10 - 17 V

Go to step 2.

Repair generator.
H4 engine model:
<Ref. to SC-<Ref. 
to SC(H4SO)-14, 
Generator.>, Gen-
erator.>
H6 engine model:
<Ref. to SC(H6)-
<Ref. to 
SC(H6DO)-14, 
Generator.>, Gen-
erator.>

2

CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
Are the positive and negative battery terminals 
tightly clamped?

Terminals are tightened 
securely.

Go to step 3.

Tighten the clamp 
of terminal.

3

CHECK INPUT VOLTAGE OF ABSCM&H/U.
1) Disconnect connector from ABSCM&H/U.
2) Run the engine at idle.
3) Measure voltage between ABSCM&H/U 

connector and chassis ground.

Connector & terminal

(F49) No. 1 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified 
range?

10 - 17 V

Go to step 4.

Repair harness 
connector 
between battery, 
ignition switch and 
ABSCM&H/U.

4

CHECK GROUND CIRCUIT OF ABSCM&H/U.
1) Turn ignition switch to OFF.
2) Measure resistance between ABSCM&H/U 

connector and chassis ground.

Connector & terminal

(F49) No. 23 — Chassis ground:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 5.

Repair 
ABSCM&H/U 
ground harness.

5

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connectors between 
generator, battery and ABSCM&H/U?

There is no poor contact.

Go to step 6.

Repair connector.

6

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 7.

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

7

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.