Subaru Legacy III (2000-2003 year). Manual - part 503

EN(H4DOSTC)-182

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AR:DTC P1111 — ATMOSPHERIC PRESSURE SENSOR CIRCUIT MALFUNC-

TION (HIGH INPUT) —

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOSTC)-35, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOSTC)-33, Inspection 
Mode.> .

Step

Value

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.
Does the Subaru Select Monitor indicate DTC 
P1111?

DTC P1111 indicated.

Replace the ECM.  
<Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

NOTE:
Atmospheric pres-
sure sensor is built
into ECM.

It is not necessary 
to inspect DTC 
P1111.

EN(H4DOSTC)-183

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4DOSTC)-184

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AS: DTC P1130 — O2 SENSOR CIRCUIT (OPEN) (BANK1 SENSOR1) —

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOSTC)-35, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOSTC)-33, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-00933

BATTERY

MAIN  RELAY

SBF-5

B47

1

2

3

5

4

6

E

E

E3

3

8

9

4

5

19

29

18

ECM

B137

B22

2

4

1

3

B18

FRONT OXYGEN
(A/F) SENSOR

3 4

1 2

3

4

1

2

5

6

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B22

B47

B18

B137

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

EN(H4DOSTC)-185

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK HARNESS BETWEEN ECM AND 
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and 

front oxygen (A/F) sensor connector.

3) Measure the resistance of harness 

between ECM and front oxygen (A/F) sen-
sor connector.

Connector & terminal

(B137) No. 29 — (B18) No. 3:
(B137) No. 19 — (B18) No. 4:

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

1 

Ω

Go to step 2.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
ECM and front 
oxygen (A/F) sen-
sor connector
• Poor contact in 
front oxygen (A/F) 
sensor connector
• Poor contact in 
ECM connector

2

CHECK POOR CONTACT.
Check poor contact in front oxygen (A/F) sen-
sor connector. 
Is there poor contact in front oxygen (A/F) sen-
sor connector?

There is poor contact.

Repair the poor 
contact in front 
oxygen (A/F) sen-
sor connector.

Replace the front 
oxygen (A/F) sen-
sor.  <Ref. to 
FU(H4DOSTC)-
38, Front Oxygen 
(A/F) Sensor.>