2004 SUBARU FORESTER check engine light

EN(H4DOTC)-195
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK SPEEDOMETER AND TACHOME-
TER OPERATION IN COMBINATION
METER.Does the speedometer and
tachometer operate normally?Go to step 2.Repair or replace
the combination
meter. 3, Combination
Meter System.>
2 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.(engine OFF)
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage less than 0.12
V?Go to step 4.Go to step 3.
3 CHECK INPUT SIGNAL FOR ECM (WITH
SUBARU SELECT MONITOR).
Read the data of fuel level sensor signal using
Subaru Select Monitor.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. 33, Subaru Select Monitor.>Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with Subaru
Select Monitor?Repair the poor
contact in ECM
connector.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
combination meter
connector
 Poor contact in
ECM connector
 Poor contact in
coupling connector
4 CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to OFF.
2) Separate fuel tank cord connector (R57)
and rear wiring harness connector (R15).
3) Turn the ignition switch to ON.
4) Measure the voltage of harness between
ECM connector and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage more than 0.12
V?Go to step 5.Go to step 6.
5 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from connector
(i10), (i11) and ECM connector.
3) Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 20 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 7.Repair the ground
short in harness
between ECM and
combination meter
connector.
6 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER.
Measure the resistance between ECM and
combination meter connector.
Connector & terminal
(B136) No. 20 — (i11) No. 1:Is the resistance less than 10
Ω?Repair or replace
the combination
meter. 3, Combination
Meter System.>Repair open circuit
between ECM and
combination meter
connector.
N
OTE:
In this case repair
the following:
Poor contact in
coupling connector

EN(H4DOTC)-198
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK SPEEDOMETER AND TACHOME-
TER OPERATION IN COMBINATION
METER.Does the speedometer and
tachometer operate normally?Go to step 2.Repair or replace
the combination
meter. 3, Combination
Meter System.>
2 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.(engine OFF)
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage more than 4.75
V?Go to step 3.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
fuel pump connec-
tor
 Poor contact in
coupling connector
3 CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the combination meter connec-
tor (i11) and ECM connector.
3) Turn the ignition switch to ON.
4) Measure the voltage of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 20 (+) — Chassis ground (
−):Is the voltage more than 4.75
V?Go to step 4.Repair battery
short circuit
between ECM and
combination meter
connector.
4 CHECK HARNESS BETWEEN ECM AND
FUEL TANK CORD.
1) Turn the ignition switch to OFF.
2) Separate fuel tank cord connector (R57)
and rear wiring harness connector (R15).
3) Measure the resistance between ECM and
fuel tank cord.
Connector & terminal
(B136) No. 20 — (R15) No. 2:Is the resistance less than 5
Ω?Go to step 5.Repair open circuit
between ECM and
fuel tank cord.
5 CHECK HARNESS BETWEEN FUEL TANK
CORD AND CHASSIS GROUND.
Measure the resistance between fuel tank cord
and chassis ground.
Connector & terminal
(R15) No. 3 — Chassis ground:Is the resistance less than 5
Ω?Go to step 6.Repair open circuit
between fuel tank
cord and chassis
ground.
N
OTE:
In this case repair
the following:
Poor contact in
coupling connector
6 CHECK FUEL TANK CORD.
1) Disconnect the connector from fuel level
sensor.
2) Measure the resistance between fuel level
sensor and coupler connector.
Connector & terminal
(R57) No. 3 — (R58) No. 5:Is the resistance less than 10
Ω?Go to step 7.Repair open circuit
between coupling
connector and fuel
level sensor.

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. 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”. 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.
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. 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. 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.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>

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. 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)-250
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”. 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 less than 0.1 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
throttle position
sensor connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
2 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground while tumble generator
valve is fully closed.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 4.Go to step 3.
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?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 connector
and chassis ground.
Connector & terminal
(B136) No. 26 (+) — Chassis ground (
−):Is the voltage less than 0.1 V? Go to step 6.Go to step 5.
5 CHECK INPUT SIGNAL FOR ECM (WITH
SUBARU SELECT MONITOR).
Measure the voltage between ECM connector
and chassis ground.Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with Subaru
Select Monitor?Repair the poor
contact in ECM
connector.Go to step 6.

EN(H4DOTC)-254
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”. 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 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 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 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)-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)-257
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 less than 0.1 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 INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground while throttle valve is fully
closed.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 4.Go to step 3.
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?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 connector
and chassis ground.
Connector & terminal
(B136) No. 27 (+) — Chassis ground (
−):Is the voltage less than 0.1 V? Go to step 6.Go to step 5.
5 CHECK INPUT SIGNAL FOR ECM (WITH
SUBARU SELECT MONITOR).
Measure the voltage between ECM connector
and chassis ground.Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with Subaru
Select Monitor?Repair the poor
contact in ECM
connector.Go to step 6.

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.>