2004 SUBARU FORESTER check engine

EN(H4DOTC)-183
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Drive the vehicle at the speed of approx. 30
km/h (19 MPH), and then measure the ignition
timing advance angle 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.Does the ignition timing
advance angle changed
smoothly according to engine
output?
Idling: −2 — +2°
Driving: −2 — +50°Repair the poor
contact connector.
N
OTE:
In this case, repair
the following:
 Poor contact of
AVCS camshaft
position sensor
connector.
 Poor contact in
ECM connector.Go to step 2.
2 CHECK HARNESS BETWEEN AVCS CAM-
SHAFT POSITION SENSOR CONNECTOR
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from AVCS cam-
shaft position sensor connector and ECM.
3) Measure the resistance of harness
between AVCS camshaft position sensor con-
nector and engine ground.
Connector & terminal
(B36) No. 1 — (B135) No. 21:
(B36) No. 2 — (B135) No. 29:Is the resistance less than 1
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
AVCS camshaft
position sensor
connector and
ECM connector
 Poor contact in
ECM connector
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN AVCS CAM-
SHAFT POSITION SENSOR CONNECTOR
AND ECM CONNECTOR.
Measure the resistance of harness between
AVCS camshaft position sensor connector and
engine ground.
Connector & terminal
(E36) No. 1 — Engine ground:
(E36) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the ground
short circuit in har-
ness between
AVCS camshaft
position sensor
connector and
ECM connector.
NOTE:
The harness be-
tween both con-
nectors are
shielded.Repair
ground short circuit
in harness togeth-
er with shield.
4 CHECK CONDITION OF AVCS CAMSHAFT
POSITION SENSOR CONNECTOR.Is the AVCS camshaft position
sensor connector installation
bolt tightened securely?Go to step 5.Tighten the AVCS
camshaft position
sensor connector
installation bolt
securely.
5 CHECK AVCS CAMSHAFT POSITION SEN-
SOR CONNECTOR.
1) Remove the AVCS camshaft position sen-
sor.
2) Measure the resistance between the AVCS
camshaft position sensor connector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 1 — 4 kΩ? Check for the clog-
ging on oil pres-
sure routing of oil
flow control sole-
noid valve.Replace the AVCS
camshaft position
sensor connector.
FU(H4DOTC)-32,
AVCS Camshaft
Position Sensor.>

EN(H4DOTC)-185
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK CURRENT DATA.
1) Start the engine.
2) Drive the vehicle at the speed of approx. 30
km/h (19 MPH), and then measure the ignition
timing advance angle 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.Does the ignition timing
advance angle changed
smoothly according to engine
output?
Idling: −2 — +2°
Driving: −2 — +50°Repair the poor
contact connector.
N
OTE:
In this case, repair
the following:
 Poor contact of
AVCS camshaft
position sensor
connector.
 Poor contact in
ECM connector.Go to step 2.
2 CHECK HARNESS BETWEEN AVCS CAM-
SHAFT POSITION SENSOR CONNECTOR
AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from AVCS cam-
shaft position sensor connector and ECM.
3) Measure the resistance of harness
between AVCS camshaft position sensor con-
nector and engine ground.
Connector & terminal
(B35) No. 1 — (B135) No. 20:
(B35) No. 2 — (B135) No. 28:Is the resistance less than 1
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
AVCS camshaft
position sensor
connector and
ECM connector
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK HARNESS BETWEEN AVCS CAM-
SHAFT POSITION SENSOR CONNECTOR
AND ECM CONNECTOR.
Measure the resistance of harness between
AVCS camshaft position sensor connector and
engine ground.
Connector & terminal
(E35) No. 1 — Engine ground:
(E35) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the ground
short circuit in har-
ness between
AVCS camshaft
position sensor
connector and
ECM connector.
NOTE:
The harness be-
tween both con-
nectors are
shielded.Repair
ground short circuit
in harness togeth-
er with shield.
4 CHECK CONDITION OF AVCS CAMSHAFT
POSITION SENSOR CONNECTOR.Is the AVCS camshaft position
sensor connector installation
bolt tightened securely?Go to step 5.Tighten the AVCS
camshaft position
sensor connector
installation bolt
securely.
5 CHECK AVCS CAMSHAFT POSITION SEN-
SOR CONNECTOR.
1) Remove the AVCS camshaft position sen-
sor connector.
2) Measure the resistance between the AVCS
camshaft position sensor connector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 1 — 4 kΩ? Check for the oil
clogging on oil
pressure routing of
oil flow control
solenoid valve.Replace the AVCS
camshaft position
sensor connector.
FU(H4DOTC)-32,
AVCS Camshaft
Position Sensor.>

EN(H4DOTC)-187
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 rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0420.Go to step 2.
2 CHECK EXHAUST SYSTEM.
Check for gas leaks or air suction caused by
loose or dislocated nuts and bolts, and open
hole at exhaust pipes.
N
OTE:
Check the following positions.
 Between cylinder head and front exhaust
pipe
 Between front exhaust pipe and front cata-
lytic converter
 Between front catalytic converter and rear
catalytic converterIs there a fault in exhaust sys-
tem?Repair or replace
the exhaust sys-
tem. EX(H4DOTC)-2,
General Descrip-
tion.>Go to step 3.
3 CHECK REAR CATALYTIC CONVERTER.
Separate rear catalytic converter from rear
exhaust pipe.Is there damage at rear face of
rear catalyst?Replace the front
and rear catalytic
converter EC(H4DOTC)-3,
Front Catalytic
Converter.> to EC(H4DOTC)-4,
Rear Catalytic
Converter.>Go to step 4.
4 CHECK FRONT CATALYTIC CONVERTER.
Remove the front catalytic converter.Is there damage at rear face or
front face of front catalyst?Replace the front
catalytic con-
verter. EC(H4DOTC)-3,
Front Catalytic
Converter.>Contact the SUB-
ARU dealer.
NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

EN(H4DOTC)-189
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):Is the voltage more than 10 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 PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from purge con-
trol solenoid valve and ECM.
3) Measure the resistance of harness
between purge control solenoid valve connec-
tor and engine ground.
Connector & terminal
(E4) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 3.Repair ground
short circuit in har-
ness between
ECM and purge
control solenoid
valve connector.
3 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
Measure the resistance of harness between
ECM and purge control solenoid valve of har-
ness connector.
Connector & terminal
(B134) No. 14 — (E4) No. 2:Is the resistance less than 1
Ω?Go to step 4.Repair open circuit
in harness
between ECM and
purge control sole-
noid valve connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and purge
control solenoid
valve connector
 Poor contact in
coupling connector
4 CHECK PURGE CONTROL SOLENOID
VALVE.
1) Remove the purge control solenoid valve.
2) Measure the resistance between purge
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 10 — 100 Ω? Go to step 5.Replace the purge
control solenoid
valve. EC(H4DOTC)-7,
Purge Control
Solenoid Valve.>
5 CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between purge control
solenoid valve and engine ground.
Connector & terminal
(E4) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 6.Repair open circuit
in harness
between main
relay and purge
control solenoid
valve connector.
6 CHECK POOR CONTACT.
Check poor contact in purge control solenoid
valve connector.Is there poor contact in purge
control solenoid valve connec-
tor?Repair poor con-
tact in purge con-
trol solenoid valve
connector.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

EN(H4DOTC)-191
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Connect the test mode connector at the
lower portion of instrument panel (on the
driver’s side).
3) Turn the ignition switch to ON.
4) While operating the purge control solenoid
valve, measure voltage between ECM and
chassis ground.
N
OTE:
Purge control solenoid valve operation can be
executed using Subaru Select Monitor.For the
procedure, refer to “Compulsory Valve Opera-
tion Check Mode”. Compulsory Valve Operation Check Mode.>
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):Is the voltage 0 — 13 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.In this
case, repair poor
contact in ECM
connector.
2 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 4.Go to step 3.
3 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).>
4 CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from purge con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in har-
ness between
ECM and purge
control solenoid
valve connec-
tor.After repair,
replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Go to step 5.
5 CHECK PURGE CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between purge
control solenoid valve terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 1
Ω?Replace the purge
control solenoid
valve and ECM.
EC(H4DOTC)-7,
Purge Control
Solenoid Valve.>
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Go to step 6.
6 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)-193
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 rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. EN(H4DOTC)-74,
List of Diagnostic
Trouble Code
(DTC).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0461.Replace the fuel
level sensor and
fuel sub level sen-
sor. FU(H4DOTC)-64,
Fuel Level Sen-
sor.> FU(H4DOTC)-65,
Fuel Sub Level
Sensor.>

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)-196
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK FUEL TANK CORD.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel sub
level sensor.
3) Measure the resistance between fuel sub
level sensor and chassis ground.
Connector & terminal
(R59) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 8.Repair ground
short circuit in fuel
tank cord.
8 CHECK FUEL TANK CORD.
1) Disconnect the connector from fuel pump
assembly.
2) Measure the resistance between fuel pump
assembly and chassis ground.
Connector & terminal
(R59) No. 2 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 9.Repair ground
short circuit in fuel
tank cord.
9 CHECK FUEL LEVEL SENSOR.
1) Remove the fuel pump assembly. FU(H4DOTC)-62, Fuel Pump.>
2) Measure the resistance between fuel level
sensor and terminals with its float set to the full
position.
Te r m i n a l s
No. 3 — No. 5:Is the resistance 0.5 — 2.5 Ω? Go to step 10.Replace the fuel
level sensor.
10 CHECK FUEL SUB LEVEL SENSOR.
1) Remove the fuel sub level sensor. FU(H4DOTC)-65, Fuel Sub Level Sensor.>
2) Measure the resistance between fuel sub
level sensor and terminals with its float set to
the full position.
Te r m i n a l s
No. 1 — No. 2:Is the resistance 0.5 — 2.5 Ω? Repair poor con-
tact in harness
between ECM and
combination meter
connector.Replace the fuel
sub level sensor. Step Check Yes No