ignition SUBARU FORESTER 2004 Service Repair Manual

EN(H4SO)-215
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
(B136) No. 21 (+) — 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
(B136) No. 21 (+) — 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
(T2) No. 1 — No. 2: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.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
(B136) No. 21 — 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
LHD MODEL
(B136) No. 21 — (B25) No. 1:
RHD MODEL
(B136) No. 21 — (B25) No. 2:Is the resistance less than 1
Ω?Go to step 8.Repair open circuit
in harness
between ECM and
transmission har-
ness connector.

EN(H4SO)-218
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 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
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 3.Go to step 5.
3 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
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage between 4.5 —
5.5 V?Go to step 4.Go to step 5.
4 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(H4SO)-44,
Engine Control
Module (ECM).>
5 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 21 (+) — 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 6.
6 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
(B136) No. 21 — (T7) No. 12:Is the resistance less than 1
Ω?Go to step 7.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.
7 CHECK INHIBITOR SWITCH GROUND LINE.
Measure the resistance of harness between
inhibitor switch connector and engine ground.
Connector & terminal
(T7) No. 7 — Engine ground:Is the resistance less than 5
Ω?Go to step 8.Repair open circuit
in harness
between inhibitor
switch connector
and ground line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
inhibitor switch
connector and
ground line

EN(H4SO)-223
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage less than 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.
N
OTE:
In this case repair
the following:
 Poor contact in
ECM connector.
 Poor contact in
TCM connector
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
TCM.
3) Measure the resistance of harness
between ECM and chassis ground.
Connector & terminal
(B134) No. 10 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in har-
ness between
ECM and TCM
connector.
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage more than 5 V? Go to step 4.Repair the poor
contact in ECM
connector.
4 CHECK DTC FOR AUTOMATIC TRANSMIS-
SION.
Read DTC for automatic transmission. 4AT(H4SO)-20, Read Diagnostic Trouble Code
(DTC).>Does the DTC appear for auto-
matic transmission?Check the DTC for
automatic trans-
mission. 4AT(H4SO)-36,
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC).>Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-225
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and TCM
connector.Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage more than 4 V? Go to step 5.Go to step 3.
3 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage less than 1 V? Repair the poor
contact in ECM
connector.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 10 (+) — Chassis ground (
−):Is the voltage 1 — 4 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.
N
OTE:
In this case repair
the following:
 Poor contact in
ECM connector.
 Poor contact in
TCM connectorContact the SUB-
ARU dealer.
NOTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.
5 CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
Measure the voltage between TCM and chas-
sis ground.
Connector & terminal
(B55) No. 17 (+) — Chassis ground (
−):Is the voltage more than 4 V? Go to step 6.Repair the open
circuit in harness
between ECM and
TCM connector.
6 CHECK POOR CONTACT.
Check poor contact in TCM connector.Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Check TCM power
supply line and
grounding line.

EN(H4SO)-230
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK FRONT (A/F) OXYGEN SENSOR DA-
TA.
1) Start the engine.
2) While observing the Subaru Select Monitor
or OBD-II general scan tool screen, warm-up
the engine until coolant temperature is above
70°C (160°F).
If the engine is already warmed-up, operate at
idle speed for at least 1 minute.
3) Read the data of front oxygen (A/F) sensor
signal at idling using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, 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 0.85 — 1.15 V? Go to step 3.Go to step 4.
3 CHECK FRONT (A/F) OXYGEN SENSOR DA-
TA.
Race the engine at speeds from idling to 5,000
rpm for a total of 5 cycles.
N
OTE:
 Normally the air fuel ratio be rich at racing.
 To increase engine speed to 5,000 rpm,
slowly depress accelerator pedal, taking
approximately 5 seconds, and quickly release
accelerator pedal to decrease engine speed.Is the voltage more than 1.1 V? Go to step 6.Go to step 4.
4 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
front oxygen (A/F) sensor connector.
3) Measure the resistance between ECM and
front oxygen (A/F) sensor.
Connector & terminal
(B136) No. 13 — (B18) No. 1:
(B136) No. 22 — (B18) No. 2:Is the resistance less than 5
Ω?Go to step 5.Repair open circuit
between ECM and
front oxygen (A/F)
sensor.
5 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 13 — Chassis ground:
(B136) No. 22 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Repair ground
short circuit
between ECM and
front oxygen (A/F)
sensor.

EN(H4SO)-234
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY TO EGR VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from EGR valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between EGR valve
connector and engine ground.
Connector & terminal
(E18) No. 2 (+) — Engine ground (
−):
(E18) No. 5 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 2.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
EGR valve and
main relay connec-
tor
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND
EGR VALVE CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the voltage between ECM and
EGR valve connector.
Connector & terminal
DTC P1492; (B134) No. 18 — (E18) No. 6:
DTC P1494; (B134) No. 17 — (E18) No. 1:
DTC P1496; (B134) No. 16 — (E18) No. 4:
DTC P1498; (B134) No. 15 — (E18) No. 3:Is the resistance less than 1
Ω?Go to step 3.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and EGR
valve connector.
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN ECM AND
EGR VALVE CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance between ECM con-
nector and chassis ground.
Connector & terminal
DTC P1492; (B134) No. 18 — Chassis
ground:
DTC P1494; (B134) No. 17 — Chassis
ground:
DTC P1496; (B134) No. 16 — Chassis
ground:
DTC P1498; (B134) No. 15 — Chassis
ground:Is the resistance more than 1
MΩ?Go to step 4.Repair ground
short in harness
between ECM and
EGR valve con-
nector.
4 CHECK POOR CONTACT.
Check poor contact in ECM connector and
EGR valve connector.Is there poor contact in ECM
connector or EGR valve con-
nector?Repair poor con-
tact in ECM con-
nector or EGR
valve connector.Replace the EGR
valve. FU(H4SO)-34,
EGR Valve.>

EN(H4SO)-236
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK GROUND CIRCUIT FOR ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 7 — Chassis ground:
(B135) No. 21 — Chassis ground:
(B137) No. 14 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM connector
and engine ground
terminal
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN ECM AND
EGR VALVE CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from EGR valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
DTC P1493; (B134) No. 18 (+) — Chassis
ground (
−):
DTC P1495; (B134) No. 17 (+) — Chassis
ground (
−):
DTC P1497; (B134) No. 16 (+) — Chassis
ground (
−):
DTC P1499; (B134) No. 15 (+) — Chassis
ground (
−):Is the voltage more than 10 V? Repair battery
short in harness
between ECM and
EGR valve con-
nector. After
repair, replace the
ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>

EN(H4SO)-239
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY TO IDLE AIR CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from idle air con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between idle air con-
trol solenoid valve connector and engine
ground.
Connector & terminal
(E7) No. 2 (+) — Engine ground (
−):
(E7) No. 5 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 2.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
idle air control
solenoid valve and
main relay connec-
tor
 Poor contact in
coupling connector
2 CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ECM and
idle air control solenoid valve connector.
Connector & terminal
DTC P1510; (B134) No. 20 — (E7) No. 4:
DTC P1512; (B134) No. 6 — (E7) No. 1:
DTC P1514; (B134) No. 5 — (E7) No. 6:
DTC P1516; (B134) No. 19 — (E7) No. 3:Is the resistance less than 1
Ω?Go to step 3.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and idle air
control solenoid
valve connector
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
1) Disconnect the connector from ECM.
2) Measure the resistance between ECM con-
nector and chassis ground.
Connector & terminal
DTC P1510; (B134) No. 20 — Chassis
ground:
DTC P1512; (B134) No. 6 — Chassis
ground:
DTC P1514; (B134) No. 5 — Chassis
ground:
DTC P1516; (B134) No. 19 — Chassis
ground:Is the resistance more than 1
MΩ?Go to step 4.Repair ground
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connector.
4 CHECK POOR CONTACT.
Check poor contact in ECM connector and idle
air control solenoid valve connector.Is there poor contact in ECM
connector or idle air control
solenoid valve connector?Repair the poor
contact in ECM
connector or idle
air control solenoid
valve connector.Replace the idle
air control solenoid
valve. FU(H4SO)-33, Idle
Air Control Sole-
noid Valve.>

EN(H4SO)-241
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK GROUND CIRCUIT FOR ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 7 — Chassis ground:
(B135) No. 21 — Chassis ground:
(B137) No. 14 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM connector
and engine ground
terminal
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN ECM AND
IDLE AIR CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from idle air con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
DTC P1511; (B134) No. 20 (+) — Chassis
ground (
−):
DTC P1513; (B134) No. 6 (+) — Chassis
ground (
−):
DTC P1515; (B134) No. 5 (+) — Chassis
ground (
−):
DTC P1517; (B134) No. 19 (+) — Chassis
ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and idle air
control solenoid
valve connector.
After repair,
replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>

EN(H4SO)-243
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-00261
12INHIBITOR SWITCH
STARTER
MOTOR
7P
RND321
SBF-4SBF-1
B14
B72
12
11
T7T3B12
13
IGNITION
SWITCH
1*2*
1*
2*
T7
123456789101112
B72
34
12
20
B136ECM
: AT MODEL
: MT MODEL1*
2*
BATTERY
B12
123456789101112
B136
5
2
84
3923 20 211011
221617
24
2512136
261915
14
1
7
18