2004 SUBARU FORESTER check engine

EN(H4SO)-193
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OPERATION OF STARTER MOTOR.
Turn the ignition switch to ON.
N
OTE:
 Place the inhibitor switch in each position.
(At model)
 Depress the clutch pedal. (MT model)Does the starter motor oper-
ate?Repair battery
short circuit in
starter motor cir-
cuit.Check starter
motor circuit. to EN(H4SO)-58,
STARTER
MOTOR CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.>

EN(H4SO)-195
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 DTC using
“List of Diagnostic
Trouble Code
(DTC)”. EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>
N
OTE:
In this case, it is not
necessary to in-
spect DTC P0519.Go to step 2.
2 CHECK AIR INTAKE SYSTEM.
1) Turn the ignition switch to ON.
2) Start the engine, and idle it.
3) Check the following items:
 Loose installation of intake manifold, idle air
control solenoid valve and throttle body
 Cracks of intake manifold gasket, idle air
control solenoid valve gasket and throttle body
gasket
 Disconnections of vacuum hosesIs there any fault in air intake
system?Repair air suction
and leaks.Go to step 3.
3 CHECK THROTTLE CABLE.Is the free play of throttle cable
appropriate?Go to step 4.Adjust throttle
cable. SP(H4SO)-9,
INSTALLATION,
Accelerator Con-
trol Cable.>
4 CHECK AIR BY-PASS LINE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve
from the throttle body. Idle Air Control Solenoid Valve.>
3) Confirm that there are no foreign particles
in air by-pass line.Are foreign particles in air by-
pass line?Remove foreign
particles from air
by-pass line.Replace the idle
air control solenoid
valve. FU(H4SO)-33, Idle
Air Control Sole-
noid Valve.>

EN(H4SO)-197
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS BETWEEN TCM AND
CRUISE CONTROL UNIT CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
cruise control unit.
3) Measure the resistance of harness
between TCM and cruise control unit connec-
tor.
Connector & terminal
(B55) No. 22 — (B94) No. 3:Is the resistance less than 1
Ω?Go to step 2.Repair open circuit
in harness
between cruise
control unit and
TCM connector.
2 CHECK HARNESS BETWEEN TCM AND
CRUISE CONTROL UNIT CONNECTOR.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 22 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit of harness
between TCM and
cruise control unit
connector.
3 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and cruise
control unit.
2) Lift up the vehicle or set it to the free roller.
CAUTION:
For AWD model, all wheels up from floor.
3) Start the engine.
4) Turn the cruise control main switch to ON.
5) Shift the select lever to “D” range and
slowly increase the vehicle speed to 50 km/h
(31 MPH).
6) Turn the cruise control command switch to
ON.
7) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 22 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 4.Check cruise con-
trol command
switch circuit.
INSPECTION,
Cruise Control
Command
Switch.>
4 CHECK POOR CONTACT.
Check poor contact in TCM connector. Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-199
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? Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>It is not necessary
to inspect DTC
P0601.

EN(H4SO)-202
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 radiator fan relay, mea-
sure the voltage between ECM and chassis
ground.
N
OTE:
Radiator fan relay operation can be executed
using Subaru Select Monitor. For procedure,
refer to “Compulsory Valve Operation Check
Mode”. Monitor.>
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):Is the voltage 0 — 10 V? Repair the poor
contact in ECM
connector.Go to step 2.
2 CHECK GROUND SHORT CIRCUIT IN RADI-
ATOR MAIN FAN RELAY CONTROL CIR-
CUIT.
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. 14 — Chassis ground:Is the resistance less than 10
Ω?Repair the ground
short circuit in
radiator main fan
relay control cir-
cuit.Go to step 3.
3 CHECK POWER SUPPLY FOR RELAY.
1) Remove the main fan relay from A/C relay
holder.
2) Turn the ignition switch to ON.
3) Measure the voltage between fuse and
relay box (F/B) connector and chassis ground.
Connector & terminal
(F27) No. 34 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 4.Repair open circuit
in harness
between ignition
switch and fuse
and relay box (F/B)
connector.
4 CHECK MAIN FAN RELAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between main fan
relay terminals.
Te r m i n a l s
No. 32 — No. 34:Is the resistance 87 — 107 Ω? Go to step 5.Replace the main
fan relay.
5 CHECK OPEN CIRCUIT IN MAIN FAN RE-
LAY CONTROL CIRCUIT.
Measure the resistance of harness between
ECM and main fan relay connector.
Connector & terminal
(B134) No. 14 — (F27) No. 32:Is the resistance less than 1
Ω?Go to step 6.Repair harness
and connector.
NOTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and main fan
relay connector
 Poor contact in
coupling connector
6 CHECK POOR CONTACT.
Check poor contact in ECM or main fan relay
connector. Is there poor contact in ECM or
main fan relay connector?Repair the poor
contact in ECM or
main fan relay con-
nector.Contact the SUB-
ARU dealer.

EN(H4SO)-205
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 radiator fan relay, mea-
sure the voltage between ECM and chassis
ground.
N
OTE:
Radiator fan relay operation can be executed
using Subaru Select Monitor. For procedure,
refer to “Compulsory Valve Operation Check
Mode”. Valve Operation Check Mode.>
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):
(B134) No. 13 (+) — Chassis ground (
−):Is the voltage 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 and sub fan
relay. (model with A/C)
3) Disconnect the test mode connectors
4) Turn the ignition switch to ON.
5) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B134) No. 14 (+) — Chassis ground (
−):
(B134) No. 13 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair battery
short circuit in
radiator fan relay
control circuit.
After repair,
replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>Go to step 3.
3 CHECK MAIN FAN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the main fan relay.
3) Measure the resistance between main fan
relay 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 and
ECM. FU(H4SO)-44,
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(H4SO)-44,
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(H4SO)-44,
Engine Control
Module (ECM).>

EN(H4SO)-207
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OPERATION OF BRAKE LIGHT.Does the brake light come on
when depressing the brake
pedal?Go to step 2.Repair or replace
the brake light cir-
cuit.
2 CHECK HARNESS BETWEEN TCM AND
BRAKE LIGHT SWITCH CONNECTOR.
1) Disconnect the connectors from TCM and
brake light switch.
2) Measure the resistance of harness
between TCM and brake light switch connec-
tor.
Connector & terminal
WITHOUT CRUISE CONTROL
(B55) No. 12 — (B64) No. 2:
WITH CRUISE CONTROL
(B55) No. 12 — (B65) No. 3:Is the resistance less than 1
Ω?Go to step 3.Repair or replace
the harness and
connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
TCM and brake
light switch con-
nector
 Poor contact in
TCM connector
 Poor contact in
brake light switch
connector
3 CHECK HARNESS BETWEEN TCM AND
BRAKE LIGHT SWITCH CONNECTOR.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 12 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair ground
short circuit in har-
ness between
TCM and brake
light switch con-
nector.
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and brake
light switch.
2) Measure the voltage between TCM and
chassis ground.
Connector & terminal
(B55) No. 12 (+) — Chassis ground (
−):Is the voltage less than 1 V
when releasing the brake
pedal?Go to step 5.Adjust or replace
the brake light
switch. 8, STOP LIGHT
SWITCH,
INSPECTION,
Stop Light Sys-
tem.>
5 CHECK INPUT SIGNAL FOR TCM.
Measure the voltage between TCM and chas-
sis ground.
Connector & terminal
(B55) No. 12 (+) — Chassis ground (
−):Is the voltage more than 10 V
when depressing the brake
pedal?Go to step 6.Adjust or replace
the brake light
switch. 8, STOP LIGHT
SWITCH,
INSPECTION,
Stop Light Sys-
tem.>
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.Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-209
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BJ:DTC P0734 GEAR 4 INCORRECT RATIO
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
 Shift point too high or too low.
 Engine brake not effected in 3rd range.
 Excessive shift shock.
 Excessive tight corner braking.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion 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(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK THROTTLE POSITION SENSOR
CIRCUIT.
Check the throttle position sensor circuit. to 4AT(H4SO)-41, DTC 31 THROTTLE POSI-
TION SENSOR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>Is there any trouble in throttle
position sensor circuit?Repair or replace
the throttle posi-
tion sensor circuit.Go to step 3.
3 CHECK FRONT VEHICLE SPEED SENSOR
CIRCUIT.
Check front vehicle speed sensor circuit. to 4AT(H4SO)-45, DTC 33 FRONT VEHICLE
SPEED SENSOR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>Is there any trouble in front
vehicle speed sensor circuit?Repair or replace
the front vehicle
speed sensor cir-
cuit.Go to step 4.
4 CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR CIRCUIT.
Check torque converter turbine speed sensor
circuit. TORQUE CONVERTER TURBINE SPEED
SENSOR, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>Is there any trouble in torque
converter turbine speed sensor
circuit?Repair or replace
the torque con-
ver ter turbine
speed sensor cir-
cuit.Go to step 5.
5 CHECK POOR CONTACT.
Check poor contact in TCM connector.Is there poor contact in TCM
connector?Repair poor con-
tact in TCM con-
nector.Go to step 6.
6 CHECK MECHANICAL TROUBLE.
Check mechanical trouble in automatic trans-
mission.Is there any mechanical trou-
ble in automatic transmission?Repair or replace
the automatic
transmission.
INSPECTION,
Road Test.>Replace the TCM.
Transmission Con-
trol Module
(TCM).>