Subaru Legacy (2005 year). Service manual — part 477

EN(H6DO)(diag)-221

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

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

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 2.

Go to step 4.

2

CHECK INPUT SIGNAL OF ECM.
1) Place the shift lever in neutral.
2) 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 3.

Go to step 4.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector.

Is there poor contact in ECM
connector?

Repair the poor
contact in ECM
connector.

Replace the ECM.

4

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

Connector & terminal

LHD model

(T2) No. 1 — No. 3:

LHD model

(T9) No. 1 — No. 3:

Is the resistance less than 1
Ω?

Go to step 5.

Repair the open
circuit in transmis-
sion harness or
replace the neu-
tral position switch.

5

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

Connector & terminal

(B137) No. 9 — (B128) No. 1:

Is the resistance less than 1
Ω?

Go to step 6.

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

6

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

Connector & terminal

(B128) No. 3 — Engine ground:

Is the resistance less than 5
Ω?

Go to step 7.

Repair the har-
ness and connec-
tor.

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

7

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

Is there poor contact in trans-
mission harness connector?

Repair poor con-
tact in transmis-
sion harness
connector.

Replace the ECM.

EN(H6DO)(diag)-222

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

CF:DTC P1160 RETURN SPRING FAILURE

NOTE:
For diagnostic procedure, refer to DTC P2101. <Ref. to EN(H6DO)(diag)-239, DTC P2101 THROTTLE AC-
TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CG:DTC P1492 EGR SOLENOID VALVE SIGNAL #1 CIRCUIT MALFUNCTION

(LOW INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1498. <Ref. to EN(H6DO)(diag)-223, DTC P1498 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CH:DTC P1493 EGR SOLENOID VALVE SIGNAL #1 CIRCUIT MALFUNCTION

(HIGH INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1499. <Ref. to EN(H6DO)(diag)-225, DTC P1499 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CI: DTC P1494 EGR SOLENOID VALVE SIGNAL #2 CIRCUIT MALFUNCTION

(LOW INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1498. <Ref. to EN(H6DO)(diag)-223, DTC P1498 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CJ:DTC P1495 EGR SOLENOID VALVE SIGNAL #2 CIRCUIT MALFUNCTION

(HIGH INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1499. <Ref. to EN(H6DO)(diag)-225, DTC P1499 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CK:DTC P1496 EGR SOLENOID VALVE SIGNAL #3 CIRCUIT MALFUNCTION

(LOW INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1498. <Ref. to EN(H6DO)(diag)-223, DTC P1498 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

CL:DTC P1497 EGR SOLENOID VALVE SIGNAL #3 CIRCUIT MALFUNCTION

(HIGH INPUT)

NOTE:
For the diagnostic procedure, refer to DTC P1499. <Ref. to EN(H6DO)(diag)-225, DTC P1499 EGR SOLE-
NOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>

EN(H6DO)(diag)-223

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

CM:DTC P1498 EGR SOLENOID VALVE SIGNAL #4 CIRCUIT MALFUNCTION

(LOW INPUT)

DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
• Erroneous idling
• Poor driving performance
• Engine breathing

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H6DO)(diag)-41,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-34, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-03502

E

B47

E18

2

5

1

4

3

6

B21

E2

E76

E77

48

3

10

9

11

8

4

7

6

SBF-7

BATTERY

MAIN RELAY

EGR

VALVE

B134

ECM

B47

3

4

1

2

5

6

B21

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

5

6

7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26 27

28

16 17

18 19 20 21

33 34

29

32

30 31

B134

10

E76

E77

21

32

33

22

B21

E2

E18

1

3

4 5 6

2

1 2

3 4

5

6

7

8

9

10

E77

6
4

EN(H6DO)(diag)-224

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK POWER SUPPLY TO EGR SOLE-
NOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from EGR sole-
noid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between EGR sole-
noid valve connector and engine ground.

Connector & terminal

(E18) No. 2 (+) — Engine ground (

−

):

(E18) No. 5 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Go to step 2.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of
harness between
EGR solenoid
valve and main
relay connector
• Poor contact in
coupling connector

2

CHECK HARNESS BETWEEN ECM AND
EGR SOLENOID VALVE CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ECM and
EGR solenoid valve connector.

Connector & terminal

DTC P1492; (B134) No. 11 — (E18) No. 3:
DTC P1494; (B134) No. 10 — (E18) No. 1:
DTC P1496; (B134) No. 9 — (E18) No. 4:
DTC P1498; (B134) No. 8 — (E18) No. 6:

Is the resistance less than 1
Ω?

Go to step 3.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of
harness between
ECM and EGR
solenoid valve
connector
• Poor contact in
coupling connector

3

CHECK HARNESS BETWEEN ECM AND
EGR SOLENOID VALVE CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance between ECM con-
nector and chassis ground.

Connector & terminal

DTC P1492; (B134) No. 11 — Chassis
ground:
DTC P1494; (B134) No. 10 — Chassis
ground:
DTC P1496; (B134) No. 9 — Chassis
ground:
DTC P1498; (B134) No. 8 — Chassis
ground:

Is the resistance more than 1
M

Ω?

Go to step 4.

Repair the ground
short in harness
between ECM and
EGR solenoid
valve connector.

4

CHECK POOR CONTACT.
Check poor contact in ECM connector and
EGR solenoid valve connector.

Is there poor contact in ECM
connector or EGR solenoid
valve connector?

Repair the poor
contact in ECM
connector or EGR
solenoid valve
connector.

Replace the EGR
solenoid valve.
<Ref. to
FU(H6DO)-25,
EGR Valve.>