Subaru Legacy III (2000-2003 year). Manual - part 162

EN(H4SO)-260

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

6

CHECK INHIBITOR SWITCH GROUND LINE.
Measure resistance of harness between inhibi-
tor switch connector and engine ground.

Connector & terminal

(T7) No. 12 — Engine ground:

Is the measured value less than the specified 
value?

5 

Ω

Go to step 7.

Repair open circuit 
in harness 
between inhibitor 
switch connector 
and starter motor 
ground line.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between  
inhibitor switch 
connector and 
starter motor 
grond line
• Poor contact in 
satrter motor con-
nector
• Poor contact in 
starter motor 
ground
• Starter motor

7

CHECK INHIBITOR SWITCH.
Measure resistance between inhibitor switch 
connector receptacle’s terminals in select level 
“N” and “P” positions.

Terminal

No. 7 — No. 12:

Is the measured value less than the specified 
value?

1 

Ω

Go to step 8.

Replace inhibitor 
switch. <Ref. to 
AT-49, Inhibitor 
Switch.>

8

CHECK SELECTOR CABLE CONNECTION.
Is there any fault in selector cable connection 
to inhibitor switch?

There is a fault.

Repair selector 
cable connection.  
<Ref. to CS-12, 
Select Cable.>

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

Step

Value

Yes

No

EN(H4SO)-261

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4SO)-262

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BO:DTC P0852 — NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL) —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Erroneous idling

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.>  and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01137

2

1

21

B136

ECM

NEUTRAL
POSITION
SWITCH

B25

T2

T2

B25

B22

E3

15

B25

1 2

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B136

5 6

7

2

1

9

8

4

3

23

21 22

24

10 11 12 13 14

25 26

15 16 17

18 19 20

EN(H4SO)-263

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 21 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value in neutral position?

5 V

Go to step 2.

Go to step 4.

2

CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis 
ground.

Connector & terminal

(B136) No. 21 (+) — Chassis ground (

−−−−

):

Is the measured value less than the specified 
value at except neutral position?

1 V

Go to step 3.

Go to step 5.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

4

CHECK NEUTRAL POSITION SWITCH.
Measure resistance between transmission har-
ness  connector terminals.

Connector & terminal

(T2) No. 1 — No. 2:

Is the measured value less than the specified 
value at except neutral position?

1 

Ω

Go to step 5.

Repair open circuit 
in transmission 
harness or replace 
neutral position 
switch.

5

CHECK HARNESS BETWEEN ECM AND 
NEUTRAL POSITION SWITCH CONNEC-
TOR.
1) Disconnect connector from ECM.
2) Measure resistance of harness between 

ECM and transmission harness connector.

Connector & terminal

(B136) No. 21 — (B25) No. 1:

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

1 

Ω

Go to step 6.

Repair open circuit 
in harness 
between ECM and 
transmission har-
ness connector.

6

CHECK HARNESS BETWEEN ECM AND 
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure resistance of harness between trans-
mission harness connector and engine ground.

Connector & terminal

(B25) No. 2 — Engine ground:

Is the measured value less than the specified 
value?

5 

Ω

Go to step 7.

Repair harness 
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
transmission har-
ness connector 
and engine 
grounding terminal
• Poor contact in 
coupling connector