2004 SUBARU FORESTER ignition

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)-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)-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)-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.

EN(H4DOTC)-251
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 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
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 har-
ness and connec-
tor.
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
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 connec-
tor.
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)-42,
Tu m b l e G e n e r a t o r
Valve Assembly.> Step Check Yes No

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)-258
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 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
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 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
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 connec-
tor.
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)-42,
Tu m b l e G e n e r a t o r
Valve Assembly.> Step Check Yes No