2004 SUBARU FORESTER meter

EN(H4DOTC)-85
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY TO FRONT OXY-
GEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from front oxygen
(A/F) sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between front oxygen
(A/F) sensor connector and engine ground.
Connector & terminal
(B262) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 2.Repair the power
supply line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
main relay and
front oxygen (A/F)
sensor
 CHECK POOR
CONTACT OF
FRONT OXYGEN
(A/F) SENSOR.
 Poor contact in
main relay connec-
tor
2 CHECK GROUND CIRCUIT FOR ECM.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis 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
ECM and engine
ground cable
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of front oxygen (A/F) sensor
heater current 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 current more than 0.2 A? Repair poor con-
tact connector.
N
OTE:
In this case repair
the following:
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — 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.Go to step 6.

EN(H4DOTC)-86
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 3 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 8.Go to step 7.
7 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 3 (+) — 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.Go to step 8.
8 CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between front oxy-
gen (A/F) sensor connector terminals.
Te r m i n a l s
No. 2 — No. 1:Is the resistance less than 10
Ω?Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open or ground
short circuit in har-
ness between front
oxygen (A/F) sen-
sor and ECM con-
nector
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Replace the front
oxygen (A/F) sen-
sor. FU(H4DOTC)-45,
Front Oxygen (A/
F) Sensor.> Step Check Yes No

EN(H4DOTC)-88
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 con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — Chassis ground (
−):Is the voltage more than 8 V? Go to step 3.Go to step 2.
2 CHECK FRONT OXYGEN (A/F) SENSOR
HEATER CURRENT.
1) Turn the ignition switch to OFF.
2) Repair the battery short circuit in harness
between ECM and front oxygen (A/F) sensor
connector.
3) Turn the ignition switch to ON.
4) Read the data of front oxygen (A/F) sensor
heater current 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 current more than 2.3 A? Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>END.
3 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — 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 battery
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.END.

EN(H4DOTC)-90
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK GROUND CIRCUIT FOR ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:Is the resistance less than 5
Ω?Go to step 2.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and engine
ground cable
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
2 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of rear oxygen (A/F) sensor
heater current using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“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 current more than 0.2 A? Repair the con-
nector.
NOTE:
In this case repair
the following:
 Poor contact in
rear oxygen sen-
sor connector
 Poor contact in
rear oxygen sen-
sor connecting
harness connector
 Poor contact in
ECM connector.Go to step 3.
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 2 (+) — 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.Go to step 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear oxygen
sensor.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>Repair battery
short circuit in har-
ness between
ECM and rear oxy-
gen sensor con-
nector.After repair,
replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>

EN(H4DOTC)-106
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 3.Go to step 2.
2 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.
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 22 (+) — Chassis ground (
−):Is the voltage less than 0.7 V? Go to step 4.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
4 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the manifold
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold
absolute pressure sensor connector and
engine ground.
Connector & terminal
(E21) No. 3 (+) — Engine ground (
−):Is the voltage more than 4.5 V? Go to step 5.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
5 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and manifold absolute pressure
sensor connector.
Connector & terminal
(B136) No. 35 — (E21) No. 2:Is the resistance less than 1
Ω?Go to step 6.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
6 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
Measure the resistance of harness between
manifold absolute pressure sensor connector
and engine ground.
Connector & terminal
(E21) No. 1 — Engine ground:Is the resistance more than 1
MΩ?Go to step 7.Repair the ground
short circuit in har-
ness between
ECM and mani-
fold absolute pres-
sure sensor
connector.
7 CHECK POOR CONTACT.
Check poor contact in manifold absolute pres-
sure sensor connector.Is there poor contact in mani-
fold absolute pressure sensor
connector?Repair poor con-
tact in manifold
absolute pressure
sensor connector.Replace the mani-
fold absolute pres-
sure sensor. to FU(H4DOTC)-
36, Manifold Abso-
lute Pressure Sen-
sor.>

EN(H4DOTC)-109
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 3.Go to step 2.
2 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.
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 22 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 4.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.
4 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the manifold
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold
absolute pressure sensor connector and
engine ground.
Connector & terminal
(E21) No. 3 (+) — Engine ground (
−):Is the voltage more than 4.5 V? Go to step 5.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
5 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM and manifold absolute pressure
sensor connector.
Connector & terminal
(B136) No. 22 — (E21) No. 1:Is the resistance less than 1
Ω?Go to step 6.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
6 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
Measure the resistance of harness between
ECM and manifold absolute pressure sensor
connector.
Connector & terminal
(B136) No. 35 — (E21) No. 2:Is the resistance less than 1
Ω?Go to step 7.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
7 CHECK POOR CONTACT.
Check poor contact in manifold absolute pres-
sure sensor connector. Is there poor contact in mani-
fold absolute pressure sensor
connector?Repair poor con-
tact in manifold
absolute pressure
sensor connector.Replace the mani-
fold absolute pres-
sure sensor. to FU(H4DOTC)-
36, Manifold Abso-
lute Pressure Sen-
sor.>

EN(H4DOTC)-126
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 0.15
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 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. 18 (+) — Chassis ground (
−):Is the voltage less than 0.15
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)-132
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
W: DTC P0129 BAROMETRIC PRESSURE TOO LOW
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
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).>
N
OTE:
In this case, it is
not necessary to
inspect DTC
P0125.Go to step 2.
2 CHECK ENGINE COOLING SYSTEM.
N
OTE:
Check the following items:
 Thermostat open stuck
 Coolant level
 Coolant freeze
 Tire diameterIs there a fault in engine cool-
ing system?Replace the ther-
mostat. CO(H4SO)-26,
Thermostat.>Replace the
engine coolant
temperature sen-
sor. FU(H4DOTC)-29,
Engine Coolant
Temperature Sen-
sor.>
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:
It is not necessary
to inspect DTC
P0129.Replace the ECM.
FU(H4DOTC)-50,
Engine Control
Module (ECM).>
NOTE:
Atmospheric pres-
sure sensor is built
in ECM.