SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC)-238
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BU:DTC P0700 TRANSMISSION CONTROL SYSTEM (MIL REQUEST)
NOTE:
For the diagnostic procedure, refer to AT section. <Ref. to 4AT(H4SO)-2, PROCEDURE, Basic Diagnostic
Procedure.>
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Connect the test mode connector.
3) Turn the ignition switch to ON.
4) While operating the radiator fan relay, mea-
sure voltage between ECM and chassis
ground.
N
OTE:
Radiator fan relay operation can be executed
using Subaru Select Monitor.For procedure, re-
fer to “Compulsory Valve Operation Check
Mode”. <Ref. to EN(H4DOTC)-48, Compulsory
Valve Operation Check Mode.>
Connector & terminal
(B135) No. 24 (+) — Chassis ground (
−):
(B135) No. 25 (+) — Chassis ground (
−):Does the voltage vary between
0 — 10 V?Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.In this
case, repair poor
contact in ECM
connector.Go to step 2.
2 CHECK SHORT CIRCUIT IN RADIATOR FAN
RELAY CONTROL CIRCUIT.
1) Turn the ignition switch to OFF.
2) Remove the main fan relay 1, sub fan relay
and fan mode relay.
3) Disconnect the test mode connectors
4) Turn the ignition switch to ON.
5) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B135) No. 24 (+) — Chassis ground (
−):
(B135) No. 25 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in
radiator fan relay
control cir-
cuit.After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Go to step 3.
3 CHECK MAIN FAN RELAY 1.
1) Turn the ignition switch to OFF.
2) Remove the main fan relay1.
3) Measure the resistance of main fan relay 1
terminals.
Te r m i n a l s
No. 30 — No. 31:Is the resistance less than 1
Ω?Replace the main
fan relay 1 and
ECM. <Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Go to step 4.
4 CHECK SUB FAN RELAY.
1) Remove the sub fan relay.
2) Measure the resistance between sub fan
relay terminals.
Te r m i n a l s
No. 28 — No. 29:Is the resistance less than 1
Ω?Replace the sub
fan relay and
ECM. <Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Go to step 5.
5 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.
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>

EN(H4DOTC)-239
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BV:DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW (AT MODEL)
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(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, OPERATION, In-
spection Mode.>.
WIRING DIAGRAM:
EN-02342
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B137ECM
9
16
E3
E
F60NEUTRAL
POSITION
SWITCH
B21
12345678910111213141516
B128
T91
B1009
LHD
RHD F2
3B128
T9
: LHD : RHD
B21
B128
1
43 2
F60
F2
M
B137
LHDRHD
MT
AT
1234 5678910 11 12 13 14 15 16 17 18 19 20
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
: LHD : RHDE2

EN(H4DOTC)-240
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Shift the select lever to other than “N” and
“P” ranges.
3) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B137) No. 9 (+) — Chassis ground (
−):Is the voltage 4.5 — 5.5 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.Go to step 2.
2 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 (T3).
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B137) No. 9 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in har-
ness between
ECM and trans-
mission harness
connector.
3 CHECK TRANSMISSION HARNESS CON-
NECTOR.
1) Disconnect the connector from inhibitor
switch.
2) Measure the resistance of harness
between transmission harness connector and
engine ground.
Connector & terminal
(T3) No. 12 — Engine ground:Is the resistance more than 1
MΩ?Go to step 4.Repair ground
short circuit in har-
ness between
transmission har-
ness and inhibitor
switch connector.
4 CHECK INHIBITOR SWITCH.
Measure the resistance between inhibitor
switch connector the receptacle’s terminals in
selector lever except for “N” range.
Te r m i n a l s
No. 7 — No. 12:Is the resistance more than 1
MΩ?Go to step 5.Replace the inhibi-
tor switch. <Ref. to
4AT-51, Inhibitor
Switch.>
5 CHECK SELECTOR CABLE CONNECTION.Is there any fault in selector
cable connection to inhibitor
switch?Repair selector
cable connection.
<Ref. to CS-14,
INSPECTION,
Select Cable.>Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

EN(H4DOTC)-241
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BW:DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW (MT MODEL)
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(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, OPERATION, In-
spection Mode.>.
WIRING DIAGRAM:
EN-02342
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B137ECM
9
16
E3
E
F60NEUTRAL
POSITION
SWITCH
B21
12345678910111213141516
B128
T91
B1009
LHD
RHD F2
3B128
T9
: LHD : RHD
B21
B128
1
43 2
F60
F2
M
B137
LHDRHD
MT
AT
1234 5678910 11 12 13 14 15 16 17 18 19 20
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
: LHD : RHDE2

EN(H4DOTC)-242
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Place the shift lever 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 FROM ECM.
1) Place the shift lever except 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.Contact the SUB-
ARU dealer.
4 CHECK NEUTRAL POSITION SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion harness.
3) Place the shift lever in neutral.
4) Measure the resistance between transmis-
sion harness and connector terminals.
Connector & terminal
(T9) No. 1 — No. 3:Is the resistance more than 1
MΩ?Go to step 5.Repair short circuit
in transmission
harness or replace
the neutral position
switch.
5 CHECK NEUTRAL POSITION SWITCH.
1) Place the shift lever except in neutral.
2) Measure the resistance between transmis-
sion harness connector terminals.
Te r m i n a l s
No. 1 — No. 3:Is the resistance less than 1
Ω?Go to step 6.Repair short circuit
in transmission
harness or replace
the neutral position
switch.
6 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B137) No. 9 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 7.Repair ground
short circuit in har-
ness between
ECM and trans-
mission harness
connector.
7 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 8.Repair open circuit
in harness
between ECM and
transmission har-
ness connector.
8 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. 1 — Engine ground:Is the resistance less than 5
Ω?Go to step 9.Repair open circuit
between transmis-
sion harness con-
nector and engine
ground terminal.
9 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.Contact the SUB-
ARU dealer.

EN(H4DOTC)-243
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BX:DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (AT MODEL)
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(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, OPERATION, In-
spection Mode.>.
WIRING DIAGRAM:
EN-02342
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B137ECM
9
16
E3
E
F60NEUTRAL
POSITION
SWITCH
B21
12345678910111213141516
B128
T91
B1009
LHD
RHD F2
3B128
T9
: LHD : RHD
B21
B128
1
43 2
F60
F2
M
B137
LHDRHD
MT
AT
1234 5678910 11 12 13 14 15 16 17 18 19 20
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
: LHD : RHDE2

EN(H4DOTC)-244
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground with select lever at “N” and “P”
ranges.
Connector & terminal
(B137) No. 9 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 2.Go to step 4.
2 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground with select lever at except “N” and
“P” ranges.
Connector & terminal
(B137) No. 9 (+) — Chassis ground (
−):Is the voltage 4.5 — 5.5 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.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
4 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B137) No. 9 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair the battery
short circuit in har-
ness between
ECM and inhibitor
switch connector.Go to step 5.
5 CHECK HARNESS BETWEEN ECM AND IN-
HIBITOR SWITCH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
inhibitor switch.
3) Measure the resistance of harness
between ECM and inhibitor switch connector.
Connector & terminal
(B137) No. 9 — (T7) No. 12:Is the resistance less than 1
Ω?Go to step 6.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and inhibitor
switch connector.
 Poor contact in
coupling connector
 Poor contact in
inhibitor switch
connector
 Poor contact in
ECM connector.

EN(H4DOTC)-245
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK INHIBITOR SWITCH GROUND LINE.
Measure the resistance of harness between
inhibitor switch connector and engine ground.
Connector & terminal
(T7) No. 7 — Engine ground:Is the resistance less than 5
Ω?Go to step 7.Repair open circuit
in harness
between inhibitor
switch connector
and starter motor
ground line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
inhibitor switch
connector and
starter motor
ground line
 Poor contact in
starter motor con-
nector
 Poor contact in
starter motor
ground
 Starter motor
7 CHECK INHIBITOR SWITCH.
Measure the resistance between inhibitor
switch connector receptacle’s terminals with
select lever at “N” and “P” ranges.
Te r m i n a l s
No. 7 — No. 12:Is the resistance less than 1
Ω?Go to step 8.Replace the inhibi-
tor switch. <Ref. to
4AT-51, Inhibitor
Switch.>
8 CHECK SELECTOR CABLE CONNECTION.Is there any fault in selector
cable connection to inhibitor
switch?Repair selector
cable connection.
<Ref. to CS-14,
INSPECTION,
Select Cable.>Contact the SUB-
ARU dealer.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts. Step Check Yes No

EN(H4DOTC)-246
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BY:DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL)
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(H4DOTC)-47, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, OPERATION, In-
spection Mode.>.
WIRING DIAGRAM:
EN-02342
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B137ECM
9
16
E3
E
F60NEUTRAL
POSITION
SWITCH
B21
12345678910111213141516
B128
T91
B1009
LHD
RHD F2
3B128
T9
: LHD : RHD
B21
B128
1
43 2
F60
F2
M
B137
LHDRHD
MT
AT
1234 5678910 11 12 13 14 15 16 17 18 19 20
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
: LHD : RHDE2

EN(H4DOTC)-247
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM 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 2.Go to step 4.
2 CHECK INPUT SIGNAL FROM 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? 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.Contact the SUB-
ARU dealer.
4 CHECK INPUT SIGNAL FROM 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 battery
short circuit in har-
ness between
ECM and trans-
mission harness
connector.Go to step 5.
5 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 switch connector.
Connector & terminal
(B137) No. 9 — (B128) No. 1:Is the resistance less than 1
Ω?Go to step 6.Repair the har-
ness and connec-
tor.
NOTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and trans-
mission harness
connector
 Poor contact in
transmission har-
ness connector.
 Poor contact in
ECM connector.
6 CHECK NEUTRAL POSITION SWITCH
GROUND LINE.
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 open circuit
in the neutral posi-
tion switch ground
line.
7 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.
Te r m i n a l s
No. 1 — No. 3:Is the resistance less than 1
Ω?Go to step 8.Replace the neu-
tral position switch.
8 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.Contact the SUB-
ARU dealer.