Subaru Legacy (2005 year). Manual - part 348

EN(H4DOTC)(diag)-161

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BA:DTC P0852 PARK/NEUTRAL SWITCH INPUT CIRCUIT HIGH

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
Erroneous idling

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

ECM

9

2

B25

T2

T2

B25

1

EN-03558

B55

NEUTRAL
POSITION
SWITCH

B137

19

TCM

B55

B137

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

AT

MT

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

E

B25

1 2

EN(H4DOTC)(diag)-162

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK TRANSMISSION TYPE.

Is the transmission type AT?

Go to step 2.

Go to step 5.

2

CHECK DTC.
Check the DTC of AT.

Is DTC of AT displayed?

Perform the diag-
nosis for AT. <Ref. 
to 5AT(diag)-35, 
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code 
(DTC).>

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
TCM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and 
TCM.
3) Measure the resistance of harness 
between ECM and TCM.

Connector & terminal

(B137) No. 9 — (B55) No. 19:

Is the resistance less than 1 
Ω?

Go to step 4.

Repair the open 
circuit of harness 
between ECM and 
TCM.

4

CHECK HARNESS BETWEEN ECM AND 
TCM.
Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Repair the poor 
contact in ECM 
and TCM connec-
tor.

Repair the ground 
short circuit of har-
ness between 
ECM and TCM.

5

CHECK INPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Place the shift lever except in neutral posi-
tion.
3) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Go to step 6.

Go to step 7.

6

CHECK INPUT SIGNAL OF ECM.
1) Place the shift lever in neutral position.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Repair the poor 

contact in ECM 
connector.

Go to step 7.

7

CHECK INPUT SIGNAL OF ECM.
1) Disconnect the connector from ECM.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Repair the battery 

short circuit of har-
ness between 
ECM and trans-
mission harness 
connector.

Go to step 8.

8

CHECK HARNESS BETWEEN ECM AND 
TRANSMISSION HARNESS CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and 
transmission harness connector (T9).
3) Measure the resistance of harness 
between ECM and neutral position switch con-
nector.

Connector & terminal

(B137) No. 9 — (B25) No. 1:

Is the resistance less than 1 
Ω?

Go to step 9.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of 
harness between 
ECM and trans-
mission harness 
connector
• Poor contact in 
transmission har-
ness connector
• Poor contact in 
ECM connector

EN(H4DOTC)(diag)-163

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BB:DTC P1160 RETURN SPRING FAILURE

NOTE:
For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4DOTC)(diag)-183, DTC P2101 THROT-
TLE ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Di-
agnostic Trouble Code (DTC).>

9

CHECK HARNESS BETWEEN NEUTRAL 
POSITION SWITCH AND ENGINE.
Measure the resistance of harness between 
transmission harness connector and engine 
ground.

Connector & terminal

(B25) No. 2 — Engine ground:

Is the resistance less than 1 
Ω?

Go to step 10.

Repair the open 
circuit in the neu-
tral position switch 
ground line.

10

CHECK NEUTRAL POSITION SWITCH.
1) Place the shift lever except in neutral posi-
tion.
2) Measure the resistance between transmis-
sion harness connector socket terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 
Ω?

Go to step 11.

Replace the neu-
tral position switch.

11

CHECK POOR CONTACT.
Check poor contact in transmission harness 
connector.

Is there poor contact in trans-
mission harness connector?

Repair the poor 
contact in trans-
mission harness 
connector.

Replace the ECM. 
<Ref. to 
FU(H4DOTC)-34, 
Engine Control 
Module (ECM).>

Step

Check

Yes

No

EN(H4DOTC)(diag)-164

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BC:DTC P1518 STARTER SWITCH CIRCUIT LOW INPUT

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
Failure of engine to start

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03518

No.21

B225

B225

MAIN SBF

SBF-6

E

16

14

15

13

ECM

B137

D:

B135

B:

B137

B72

D:

B135

B:

B32

D8

B72

B14

3

2

M

10

11 12

13
14

15 16

17
18

19 20

21
22

23 24

25
26

27 28

29

30

31 32

33
34

35 36

39 40

37
38

1

2

9

3

4

5

6

7

8

1

2

7

8 9

5

6

3

4

10 11 12

19 20 21

29

30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

1

2

7

8 9

5

6

3

4

10 11 12

19

20 21

29 30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

32 33

34 35

1

3

4 5 6

2

BATTERY

IGNITION
SWITCH

STARTER RELAY

STARTER MOTOR