Subaru Legacy III (2000-2003 year). Manual - part 368

EN(H6DO)-274

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BR:DTC P0661 — INTAKE MANIFOLD TUNING VALVE CONTROL CIRCUIT 

LOW - BANK 1 —

• 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(H6DO)-54, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)-47, OPERATION, Inspec-
tion Mode.>.
• WIRING DIAGRAM:

EN-01097

23

B20

E1

1

2

7

4

E30

SBF-5

B137

B20

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

E30

B47

3

4

1

2

5

6

BATTERY

B137

ECM

B47

MAIN RELAY

INDUCTION VALVE
CONTROL SOLENOID

1

2

3

5

4

6

1 2

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

F46

3 4

1 2

B108

F46

2

RHD

LHD

LHD

RHD

EN(H6DO)-275

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

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

sis ground.

Connector & terminal

(B137) No. 23 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Even if MI lights 
up, the circuit has 
returned to a nor-
mal condition at 
this time. Contact 
SUBARU distribu-
tor service.

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

Go to step 2.

2

CHECK HARNESS BETWEEN INDUCTION 
CONTROL SOLENOID VALVE AND ECM 
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from induction con-

trol solenoid valve and ECM.

3) Measure resistance of harness between 

induction control solenoid valve connector 
and engine ground.

Connector & terminal

(E30) No. 2 — Engine ground:

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

10 

Ω

Repair ground 
short circuit in har-
ness between 
ECM and induc-
tion control sole-
noid valve 
connector.

Go to step 3.

3

CHECK HARNESS BETWEEN INDUCTION 
CONTROL SOLENOID VALVE AND ECM 
CONNECTOR.
Measure resistance of harness between ECM 
and induction control solenoid valve of harness 
connector.

Connector & terminal

(B137) No. 23 — (E30) No. 2:

Is the measured value less than the specified 
value?

1 

Ω

Go to step 4.

Repair open circuit 
in harness 
between ECM and 
induction control 
solenoid valve 
connector.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
ECM and induc-
tion control sole-
noid valve 
connector
• Poor contact in 
coupling connector

4

CHECK INDUCTION CONTROL SOLENOID 
VALVE.
1) Remove induction control solenoid valve.
2) Measure resistance between induction con-

trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the measured value within the specified 
range?

37 — 44 

Ω

Go to step 5.

Replace induction 
control solenoid 
valve. <Ref. to 
FU(H6DO)-38, 
Induction Valve 
Control Solenoid.>

EN(H6DO)-276

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

5

CHECK POWER SUPPLY TO INDUCTION 
CONTROL SOLENOID VALVE.
1) Turn ignition switch to ON.
2) Measure voltage between induction control 

solenoid valve and engine ground.

Connector & terminal

(E30) No. 1 (+) — Engine ground (

−−−−

):

Is the measured value within the specified 
range?

10 V

Go to step 6.

Repair open circuit 
in harness 
between main 
relay and induction 
control solenoid 
valve connector.

6

CHECK POOR CONTACT.
Check poor contact in induction control sole-
noid valve connector.
Is there poor contact in induction control sole-
noid valve connector?

There is poor contact.

Repair poor con-
tact in induction 
control solenoid 
valve connector.

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(H6DO)-277

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO: