check engine SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC)-261
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 DIS-
PLAY FOR ENGINE”. 33, 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 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 har-
ness and connec-
tor.
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)-50,
Engine Control
Module (ECM).>Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tu m b l e G e n e r a t o r
Valve Assembly.>

EN(H4DOTC)-262
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
CD:DTC P1090 TUMBLE GENERATED VALVE SYSTEM 1 (VALVE OPEN)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
CE:DTC P1091 TUMBLE GENERATED VALVE SYSTEM 1 (VALVE CLOSE)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
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)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>Go to step 2.
2 CHECK TUMBLE GENERATOR VALVE RH.
1) Remove the tumble generator valve assem-
bly.
2) Check tumble generator valve body.Does the tumble generator
valve move smoothly? (No dirt
or foreign materials clogged)Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tumble Generator
Valve Assembly.>Clean tumble gen-
erator valve.
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)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>Go to step 2.
2 CHECK TUMBLE GENERATOR VALVE RH.
1) Remove the tumble generator valve assem-
bly.
2) Check tumble generator valve body.Does the tumble generator
valve move smoothly? (No dirt
or foreign materials clogged)Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tumble Generator
Valve Assembly.>Clean tumble gen-
erator valve.

EN(H4DOTC)-263
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
CF:DTC P1092 TUMBLE GENERATED VALVE SYSTEM 2 (VALVE OPEN)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
CG:DTC P1093 TUMBLE GENERATED VALVE SYSTEM 2 (VALVE CLOSE)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
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)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>Go to step 2.
2 CHECK TUMBLE GENERATOR VALVE RH.
1) Remove the tumble generator valve assem-
bly.
2) Check tumble generator valve body.Does the tumble generator
valve move smoothly? (No dirt
or foreign materials clogged)Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tumble Generator
Valve Assembly.>Clean tumble gen-
erator valve.
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)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>Go to step 2.
2 CHECK TUMBLE GENERATOR VALVE RH.
1) Remove the tumble generator valve assem-
bly.
2) Check tumble generator valve body.Does the tumble generator
valve move smoothly? (No dirt
or foreign materials clogged)Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tumble Generator
Valve Assembly.>Clean tumble gen-
erator valve.

EN(H4DOTC)-265
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 — (B135) 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 connec-
tor.Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tu m b l e G e n e r a t o r
Valve Assembly.>

EN(H4DOTC)-267
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)-42,
Tumble Generator
Valve Assembly.>Repair the battery
short circuit
between ECM and
tumble generator
valve actuator.

EN(H4DOTC)-269
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 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 connec-
tor.Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tu m b l e G e n e r a t o r
Valve Assembly.>

EN(H4DOTC)-271
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
CL:DTC P1110 ATMOSPHERIC PRESSURE SENSOR CIRCUIT MALFUNCTION
(LOW INPUT)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
CM:DTC P1111 ATMOSPHERIC PRESSURE SENSOR CIRCUIT MALFUNCTION
(HIGH INPUT)
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode .
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
(E51) No. 1 (+) — Chassis ground (
−):
(E51) No. 2 (+) — Chassis ground (
−):Is the voltage less than 5 V? Replace the tum-
ble generator valve
assembly. FU(H4DOTC)-42,
Tumble Generator
Valve Assembly.>Repair the battery
short circuit
between ECM and
tumble generator
valve actuator.
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Does the Subaru Select Moni-
tor or OBD-II general scan tool
indicate DTC P1110?Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>
N
OTE:
Atmospheric pres-
sure sensor is built
in ECM.Temporary poor
contact occurs.
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Does the Subaru Select Moni-
tor or OBD-II general scan tool
indicate DTC P1111?Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>
NOTE:
Atmospheric pres-
sure sensor is built
in ECM.Temporary poor
contact occurs.

EN(H4DOTC)-273
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check 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 connector from ECM and
front oxygen (A/F) sensor connector.
3) Measure the resistance of harness
between ECM and front oxygen (A/F) sensor
connector.
Connector & terminal
(B134) No. 26 — (B18) No. 3:
(B134) No. 33 — (B18) No. 4:Is the resistance less than 1
Ω?Go to step 2.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Check harness
between ECM and
front oxygen (A/F)
sensor 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 any poor contact in
front oxygen (A/F) sensor con-
nector?Repair the poor
contact in front
oxygen (A/F) sen-
sor connector.Replace the front
oxygen (A/F) sen-
sor. FU(H4DOTC)-45,
Front Oxygen (A/
F) Sensor.>

EN(H4DOTC)-275
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check 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 connector from ECM and
front oxygen (A/F) sensor.
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B134) No. 33 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 2.Repair the ground
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.
2 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 26 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the ground
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.
3 CHECK OUTPUT SIGNAL FOR ECM.
1) Connect the connector to ECM and front
oxygen (A/F) sensor.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 33 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 4.Go to step 5.
4 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 33 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair the battery
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.After
repair, replace the
ECM. FU(H4DOTC)-50,
Engine Control
Module (ECM).>Repair the poor
contact in ECM
connector.
5 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 19 (+) — Chassis ground (
−):Is the voltage more than 4.95
V?Go to step 6.Replace the front
oxygen (A/F) sen-
sor. FU(H4DOTC)-45,
Front Oxygen (A/
F) Sensor.>
6 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 26 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair the battery
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.After
repair, replace the
ECM. FU(H4DOTC)-50,
Engine Control
Module (ECM).>Repair the poor
contact in ECM
connector.

EN(H4DOTC)-277
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK DTC.
Conduct the troubleshooting for all DTC
P0301, P0302, P0303 and P0304. EN(H4DOTC)-74, List of Diagnostic Trouble
Code (DTC).>Does failure for repair or
replacement exist?Repair or replace
failure, then
replace the precat-
alytic converter.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.