2004 SUBARU FORESTER ignition

EN(H4DOTC 2.5)-172
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AT:DTC P0638 THROTTLE ACTUATOR CONTROL RANGE/PERFORMANCE
(BANK 1)
NOTE:
For diagnostic procedure, refer to DTC P2101. TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
Step Check Yes No
1 CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and ground.
Connector & terminal
(B135) No. 5 (+) — Chassis ground (
−):
(B135) No. 6 (+) — Chassis ground (
−):Is the voltage 10 — 13 V? Go to step 2.Repair open or
ground short cir-
cuit of power sup-
ply circuit.
2 CHECK INPUT VOLTAGE OF ECM.
1) Start the engine.
2) Measure the voltage between ECM con-
nector and ground.
Connector & terminal
(B135) No. 5 (+) — Chassis ground (
−):
(B135) No. 6 (+) — Chassis ground (
−):Is the voltage 13 — 15 V? Go to step 3.Repair open or
ground short cir-
cuit of power sup-
ply circuit.
3 CHECK ECM GROUND HARNESS.
Measure the voltage between ECM connector
and ground.
Connector & terminal
(B137) No. 1 (+) — Chassis ground (
−):
(B137) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.Further tighten the
engine ground ter-
minal.

EN(H4DOTC 2.5)-174
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02410
No.18
No.17
EE
SBF-4
SBF-1
F17
B135 ECM
25
24F16
F16B72F27
F17
3412
1
2
SUB FAN
MOTOR
M
1
2
MAIN FAN
MOTOR
M
BATTERY
IGNITION
SWITCHB72
41
3132333435
36
56789
1011121314
1516171819
2021222324
2526272829
1230
34
20A
F27 FAN
MODE
RELAY
A/C RELAY HOLDER
MAIN
FAN
RELAY SUB
FAN
RELAY
20A
29
25
27
28
30
34
32
317
5
9
2
1
4
3 8 6
B100F2
12
B135
567
82 1
94 310
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
7
19
F2
12345 678910
11
1219 20 21
13 14 15 1617
18 22

EN(H4DOTC 2.5)-175
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
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 terminal and ground.
N
OTE:
Radiator fan relay operation can be executed
using Subaru Select Monitor. For procedure,
refer to “Compulsory Valve Operation Check
Mode”. Select Monitor.>
Connector & terminal
(B135) No. 24 (+) — Chassis ground (
−):
(B135) No. 25 (+) — Chassis ground (
−):Does the voltage vary between
0 — 10 V?Repair the poor
contact in ECM
connector.Go to step 2.
2 CHECK GROUND SHORT CIRCUIT IN RADI-
ATOR FAN RELAY CONTROL CIRCUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B135) No. 24 — Chassis ground:
(B135) No. 25 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in
radiator fan relay
control circuit.
3 CHECK POWER SUPPLY FOR RELAY.
1) Remove the main fan relay and sub fan relay
from A/C relay holder.
2) Turn the ignition switch to ON.
3) Measure the voltage between fuse and
relay box (F/B) connector and chassis ground.
Connector & terminal
(F27) No. 27 (+) — Chassis ground (
−):
(F27) No. 32 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 4.Repair open circuit
in harness
between ignition
switch and fuse
and relay box (F/B)
connector.
4 CHECK FAN RELAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between fan relay
terminals.
Te r m i n a l s
No. 32 — No. 34 (Main fan relay)
No. 25 — No. 27 (Sub fan relay)Is the resistance 87 — 107 Ω? Go to step 5.Replace the fan
relay.
5 CHECK OPEN CIRCUIT IN FAN RELAY
CONTROL CIRCUIT.
Measure the resistance of harness between
ECM and fan relay connector.
Connector & terminal
(B135) No. 24 — (F27) No. 27:
(B135) No. 25 — (F27) No. 32:Is the resistance less than 1
Ω?Go to step 6.Repair harness
and connector.
NOTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and fan relay
connector
 Poor contact in
coupling connector
6 CHECK POOR CONTACT.
Check poor contact in ECM or fan relay connector.Is there poor contact in ECM or
fan relay connector?Repair the poor
contact in ECM or
fan relay connector.Contact the SUB-
ARU dealer.

EN(H4DOTC 2.5)-177
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02410
No.18
No.17
EE
SBF-4
SBF-1
F17
B135 ECM
25
24F16
F16B72F27
F17
3412
1
2
SUB FAN
MOTOR
M
1
2
MAIN FAN
MOTOR
M
BATTERY
IGNITION
SWITCHB72
41
3132333435
36
56789
1011121314
1516171819
2021222324
2526272829
1230
34
20A
F27 FAN
MODE
RELAY
A/C RELAY HOLDER
MAIN
FAN
RELAY SUB
FAN
RELAY
20A
29
25
27
28
30
34
32
317
5
9
2
1
4
3 8 6
B100F2
12
B135
567
82 1
94 310
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
7
19
F2
12345 678910
11
1219 20 21
13 14 15 1617
18 22

EN(H4DOTC 2.5)-178
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AW:DTC P0700 TRANSMISSION CONTROL SYSTEM (MIL REQUEST)
NOTE:
For the diagnostic procedure, refer to AT section. 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,
refer to “Compulsory Valve Operation Check
Mode”. sory 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, 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 radi-
ator fan relay con-
trol circuit. After
repair, replace the
ECM. FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Go to step 3.
3 CHECK FAN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the fan relay.
3) Measure the resistance between fan relay
terminals.
Te r m i n a l s
No. 30 — No. 31 (Main fan relay)
No. 28 — No. 29 (Sub fan relay)Is the resistance less than 1
Ω?Replace the fan
relay and ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Go to step 4.
4 CHECK FAN MODE RELAY.
1) Remove the fan mode relay.
2) Measure the resistance between fan mode
relay terminals.
Te r m i n a l s
No. 8 — No. 9: (Fan mode relay)Is the resistance less than 1
Ω?Replace the fan
mode relay and
ECM. FU(H4DOTC 2.5)-
41, Engine Con-
trol 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.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>

EN(H4DOTC 2.5)-180
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. 4AT-51, Inhibitor
Switch.>
5 CHECK SELECTOR CABLE CONNECTION.Is there any fault in selector cable
connection to inhibitor switch?Repair selector
cable connection.
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 2.5)-182
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 connector.
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 transmission
harness connector.Contact the SUB-
ARU dealer.

EN(H4DOTC 2.5)-184
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, because
probable cause is
deterioration of mul-
tiple 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.
NOTE:
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.