2004 SUBARU FORESTER ignition

EN(H4DOTC 2.5)-187
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 harness
and connector.
N
OTE:
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 contact
in transmission har-
ness connector.Contact the SUB-
ARU dealer.

EN(H4DOTC 2.5)-190
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE POSITION
SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve position sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between tumble gen-
erator valve position sensor connector and
engine ground.
Connector & terminal
(E50) No. 1 (+) — Engine ground (
−):Is the voltage more than 4.5 V? Go to step 7.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
tumble generator
valve position sen-
sor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
 Poor contact in
joint connector
7 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE POSITION
SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between ECM connector and tumble generator
valve position sensor connector.
Connector & terminal
(B136) No. 26 — (E50) No. 3:Is the resistance less than 1
Ω?Go to step 8.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
ECM connector.
 Poor contact in
tumble generator
valve position sen-
sor connector
 Poor contact in
coupling connector
8 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE POSITION
SENSOR CONNECTOR.
Measure the resistance of harness between
tumble generator valve position sensor con-
nector and engine ground.
Connector & terminal
(E50) No. 3 — Engine ground:Is the resistance more than 1
MΩ?Go to step 9.Repair ground
short circuit in har-
ness between tum-
ble generator valve
position sensor and
ECM connector.
9 CHECK POOR CONTACT.
Repair poor contact in tumble generator valve
position sensor connector.Is there poor contact in tumble
generator valve position sen-
sor connector?Repair the poor
contact in tumble
generator valve
position sensor
connector.Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.> Step Check Yes No

EN(H4DOTC 2.5)-192
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 throttle position sensor
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”. 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 voltage more than 4.9 V? Go to step 2.Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector
may be the cause.
N
OTE:
In this case repair
the following:
 Poor contact in
tumble generator
valve position sen-
sor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN TUMBLE
GENERATOR VALVE POSITION SENSOR
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from throttle
position sensor.
3) Measure the resistance of harness
between throttle position sensor connector and
engine ground.
Connector & terminal
(E50) No. 2 — Engine ground:Is the resistance less than 5
Ω?Go to step 3.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
coupling connector
 Poor contact in
joint connector
3 CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND ECM CONNEC-
TOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between throttle posi-
tion sensor connector and engine ground.
Connector & terminal
(E50) No. 3 (+) — Engine ground (
−):Is the voltage more than 4.9 V? Repair battery
short circuit in har-
ness between tum-
ble generator valve
position sensor
and ECM connec-
tor. After repair,
replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.>

EN(H4DOTC 2.5)-195
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE POSITION
SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from throttle
position sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between throttle posi-
tion sensor connector and engine ground.
Connector & terminal
(E54) No. 1 (+) — Engine ground (
−):Is the voltage more than 4.5 V? Go to step 7.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
throttle position
sensor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
 Poor contact in
joint connector
7 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE POSITION
SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between ECM connector and throttle position
sensor connector.
Connector & terminal
(B136) No. 27 — (E54) No. 3:Is the resistance less than 1
Ω?Go to step 8.Repair the harness
and connector.
NOTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
ECM connector.
 Poor contact in
tumble generator
valve position sen-
sor connector
 Poor contact in
coupling connector
8 CHECK HARNESS BETWEEN ECM AND
THROTTLE POSITION SENSOR CONNEC-
TOR.
Measure the resistance of harness between
tumble generator valve position sensor con-
nector and engine ground.
Connector & terminal
(E54) No. 3 — Engine ground:Is the resistance more than 1
MΩ?Go to step 9.Repair ground
short circuit in har-
ness between tum-
ble generator valve
position sensor and
ECM connector.
9 CHECK POOR CONTACT.
Repair poor contact in tumble generator valve
position sensor connector.Is there poor contact in tumble
generator valve position sen-
sor connector?Repair the poor
contact in tumble
generator valve
position sensor
connector.Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.> Step Check Yes No

EN(H4DOTC 2.5)-197
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 tumble generator valve
position sensor 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 DISPLAY FOR
ENGINE”. aru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the voltage more than 4.9 V? Go to step 2.Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector
may be the cause.
N
OTE:
In this case repair
the following:
 Poor contact in
tumble generator
valve position sen-
sor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN TUMBLE
GENERATOR VALVE POSITION SENSOR
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from throttle
position sensor.
3) Measure the resistance of harness
between tumble generator valve position sen-
sor connector and engine ground.
Connector & terminal
(E54) No. 2 — Engine ground:Is the resistance less than 5
Ω?Go to step 3.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
tumble generator
valve position sen-
sor and ECM con-
nector
 Poor contact in
coupling connector
 Poor contact in
joint connector
3 CHECK HARNESS BETWEEN TUMBLE
GENERATOR VALVE POSITION SENSOR
AND ECM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between throttle posi-
tion sensor connector and engine ground.
Connector & terminal
(E54) No. 3 (+) — Engine ground (
−):Is the voltage more than 4.9 V? Repair battery
short circuit in har-
ness between tum-
ble generator valve
position sensor
and ECM connec-
tor. After repair,
replace the ECM.
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.>

EN(H4DOTC 2.5)-202
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE ACTUATOR
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve and ECM connector.
3) Measure the resistance between tumble
generator valve actuator and ECM connector.
Connector & terminal
(E55) No. 1 — (B134) No. 9:
(E55) No. 2 — (B134) No. 8:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit between
ECM and tumble
generator valve
connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and tumble
generator valve
actuator connec-
tor.
 Poor contact in
coupling connector
2 CHECK POOR CONTACT.
Check poor contact in tumble generator valve
actuator connector.Is there poor contact in tumble
generator valve actuator con-
nector.Repair the poor
contact in tumble
generator valve
actuator connector.Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.>

EN(H4DOTC 2.5)-204
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE ACTUATOR
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve connector.
3) Measure the voltage between tumble gen-
erator valve actuator and chassis ground.
Connector & terminal
(E55) No. 1 (+) — Chassis ground (
−):
(E55) No. 2 (+) — Chassis ground (
−):Is the voltage less than 5 V? Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.>Repair the battery
short circuit
between ECM and
tumble generator
valve actuator.

EN(H4DOTC 2.5)-206
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TUMBLE GENERATOR VALVE ACTUATOR
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve and ECM connector.
3) Measure the resistance between tumble
generator valve actuator and ECM connector.
Connector & terminal
(E51) No. 1 — (B134) No. 11:
(E51) No. 2 — (B134) No. 10:Is the resistance less than 1 Ω? Go to step 2.Repair the open
circuit between
ECM and tumble
generator valve
connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and tumble
generator valve
actuator connector.
 Poor contact in
coupling connector
2 CHECK POOR CONTACT.
Check poor contact in tumble generator valve
actuator connector.Is there poor contact in tumble
generator valve actuator con-
nector?Repair the poor
contact in tumble
generator valve
actuator connector.Replace the tum-
ble generator valve
assembly. FU(H4DOTC 2.5)-
33, Tumble Gener-
ator Valve Assem-
bly.>