SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC 2.5)-157
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AM:DTC P0519 IDLE CONTROL SYSTEM MALFUNCTION (FAIL-SAFE)
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Engine keeps running at higher revolution than specified idling revolution.
 Fuel is cut according to fail-safe function.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.

EN(H4DOTC 2.5)-158
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02364
B317
34
12
B22
125678
131415169101112
34
17181920
B21
123
4
56
78
9
1011 12
1314 15 16
B83
1
23456
B135
567
82 1
94 3
10
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B:
B35D6
B135 B: C:
D4 D3
C18
B1 C35
D1 B4
D2
SBF-5
2
1
3
4
E
E57
3
6 4
1
2 2
3
15
16
E
5
EE
B137 D:ECM B309
B136
B122
1
E2 B21
E3 B22 B317
E56B47 35
2 1
4 3
D5C16C29
19122018
MAIN RELAYBATTERY
ELECTRONIC
THROTTLE
CONTROL ELECTRONIC
THROTTLE
CONTROL
RELAY
B83
B122
123456783412
56
B47
B137
567
82 1
94 3
10
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B136
56
782 1
94 3
10
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B309
34
12
E57

EN(H4DOTC 2.5)-159
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4DOTC 2.5)-
65, List of Diag-
nostic Trouble
Code (DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0519.Go to step 2.
2 CHECK AIR INTAKE SYSTEM.
1) Turn the ignition switch to ON.
2) Start and idle the engine.
3) Check the following items:
 Loose installation of intake manifold and
throttle body
 Cracks of intake manifold gasket and throttle
body gasket
 Disconnections of vacuum hosesIs there any fault in air intake
system?Repair air suction
and leaks.Go to step 3.
3 CHECK ELECTRONIC THROTTLE CON-
TROL.
1) Turn the ignition switch to OFF.
2) Replace the electronic throttle control.
3) Check the electronic throttle control.Are foreign matters found
inside the electronic throttle
control?Remove foreign
matters from the
electronic throttle
control.Perform the diag-
nosis of DTC
P2101.

EN(H4DOTC 2.5)-160
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AN:DTC P0545 EXHAUST GAS TEMPERATURE SENSOR CIRCUIT LOW - BANK 1
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Hard to start
 Erroneous idling
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
EN-02369
B1226
B136 ECM
35 24
B2791
2
B279
112
B122
B136
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
EXHAUST GAS
TEMPERATURE
SENSOR
12345678

EN(H4DOTC 2.5)-161
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of exhaust temperature sen-
sor signal using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the temperature more than
1,200°C (2,192°F)?Go to step 2.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact of
exhaust tempera-
ture sensor
 Poor contact in
ECM
 Poor contact in
joint connector
2 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust
temperature sensor.
3) Turn the ignition switch to ON.
4) Read the data of exhaust temperature sen-
sor signal using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the temperature less than
372°C (702°F)?Replace the
exhaust tempera-
ture sensor. <Ref.
to FU(H4DOTC
2.5)-40, Exhaust
Temperature Sen-
sor.>Repair ground
short circuit in har-
ness between
exhaust tempera-
ture sensor and
ECM connector.

EN(H4DOTC 2.5)-162
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AO:DTC P0546 EXHAUST GAS TEMPERATURE SENSOR HIGH - BANK 1
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Hard to start
 Erroneous idling
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
EN-02369
B1226
B136 ECM
35 24
B2791
2
B279
112
B122
B136
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
EXHAUST GAS
TEMPERATURE
SENSOR
12345678

EN(H4DOTC 2.5)-163
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of exhaust temperature sen-
sor signal using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the temperature less than
372°C (702°F)?Go to step 2.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact of
exhaust tempera-
ture sensor
 Poor contact in
ECM
 Poor contact in
joint connector
2 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust
temperature sensor.
3) Measure the voltage between exhaust tem-
perature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and exhaust
temperature sen-
sor connector.Go to step 3.
3 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between exhaust tem-
perature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and exhaust
temperature sen-
sor connector.Go to step 4.
4 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
Measure the voltage between exhaust temper-
ature sensor connector and engine ground.
Connector & terminal
(B279) No. 1 (+) — Engine ground (
−):Is the voltage more than 4 V? Go to step 5.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and exhaust
temperature sen-
sor connector
 Poor contact of
exhaust tempera-
ture sensor con-
nector
 Poor contact in
ECM connector.
 Poor contact in
joint connector

EN(H4DOTC 2.5)-164
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK HARNESS BETWEEN EXHAUST
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between exhaust temperature sensor connec-
tor and engine ground.
Connector & terminal
(B279) No. 2 — Engine ground:Is the resistance less than 5
Ω?Replace the
exhaust tempera-
ture sensor. <Ref.
to FU(H4DOTC
2.5)-40, Exhaust
Temperature Sen-
sor.>Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and exhaust
temperature sen-
sor connector
 Poor contact of
exhaust tempera-
ture sensor con-
nector
 Poor contact in
ECM connector.
 Poor contact in
joint connector Step Check Yes No

EN(H4DOTC 2.5)-165
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AP:DTC P0600 SERIAL COMMUNICATION LINK
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
AT-01524
18
263
12
B55
B137
ECM
B55 TCM
B137
12
7
8956 3410 11 12
19 20 2113 14 15 16
17 1822
23
24
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
TWISTED WIRE

EN(H4DOTC 2.5)-166
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TCM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from TCM.
4) Measure the resistance between ECM and
TCM connectors.
Connector & terminal
(B137) No. 18 — (B55) No. 3:
(B137) No. 26 — (B55) No. 12:Is the resistance less than 1
Ω?Go to step 2.Repair the harness
and connector.
2 CHECK HARNESS BETWEEN ECM AND
TCM.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B137) No. 18 — Chassis ground:
(B137) No. 26 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the harness
and connector.
3 CHECK HARNESS BETWEEN ECM AND
TCM.
Check the resistance between ECM connec-
tors.
Connector & terminal
(B137) No. 18 — (B137) No. 26:Is the resistance more than 1
MΩ?Go to step 4.Repair the harness
and connector.
4 CHECK AT SYSTEM CONDITION.
Perform the diagnosis for AT using Subaru
Select Monitor.Is DTC P1718 displayed? Check AT system. Replace the ECM.