2004 SUBARU FORESTER check engine light

EN(H4SO)-2
ENGINE (DIAGNOSTIC)
Basic Diagnostics Procedure
1. Basic Diagnostics Procedure
A: PROCEDURE
1. ENGINE
Step Check Yes No
1 CHECK ENGINE START FAILURE.
1) Ask the customer when and how the trou-
ble occurred using the interview check list.
List for Interview.>
2) Start the engine.Does the engine start? Go to step 2.Inspection using
“Diagnostics for
Engine Starting
Failure”. EN(H4SO)-57,
Diagnostics for
Engine Starting
Fai lu r e.>
2 CHECK ILLUMINATION OF MALFUNCTION
INDICATOR LIGHT.Does malfunction indicator
light illuminate?Go to step 3.Inspection using
“General Diagnos-
tic Table”. EN(H4SO)-255,
INSPECTION,
General Diagnos-
tic Table.>
3 CHECK INDICATION OF DTC ON DISPLAY
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor or the
OBD-II general scan tool to data link connec-
tor.
3) Turn the ignition switch to ON and the Sub-
aru Select Monitor or OBD-II general scan tool
switch to ON.
4) Read the DTC on the Subaru Select Moni-
tor or OBD-II general scan tool.Does the Subaru Select Moni-
tor or OBD-II general scan tool
indicate DTC?Record the DTC.
Repair the trouble
cause. EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>
Go to step 4.Repair the related
parts.
N
OTE:
If DTC is not shown
on display although
the engine warning
light illuminates, per-
form the diagnostics
of engine warning
light circuit or combi-
nation meter. to EN(H4SO)-47,
Malfunction Indica-
tor Light.>
4 PERFORM THE DIAGNOSIS.
1) Perform the Clear Memory Mode. EN(H4SO)-44, Clear Memory Mode.>
2) Perform the Inspection Mode. EN(H4SO)-37, Inspection Mode.>Does the Subaru Select Moni-
tor or OBD-II general scan tool
indicate DTC?Check on “Diag-
nostic Procedure
with Diagnostic
Trouble Code
(DTC)”
EN(H4SO)-78,
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC).>Finish the diagno-
sis.

EN(H4SO)-4
ENGINE (DIAGNOSTIC)
Check List for Interview
2. Check List for Interview
A: INSPECTION
1. CHECK LIST No. 1
Check the following items when problem has occurred.
NOTE:
Use copies of this page for interviewing customers.
Customer’s name Engine No.
Date of sale Fuel brand
Date of repair
Odometer readingkm
V.I.N.miles
Weather❏ Fine
❏ Cloudy
❏ Rainy
❏ Snowy
❏ Va r i o u s / O t h e r s :
Ambient air temperature°C (°F)
❏ Hot
❏ War m
❏ Cool
❏ Cold
Place❏ Highway
❏ Suburbs
❏ Inner city
❏ Uphill
❏ Downhill
❏ Rough road
❏ Others:
Engine temperature❏ Cold
❏ War ming-up
❏ After warming-up
❏ Any temperature
❏ Others:
Engine speed rpm
Vehicle speed km/h (MPH)
Driving conditions❏ Not affected
❏ At starting
❏ While idling
❏ At racing
❏ While accelerating
❏ While cruising
❏ While decelerating
❏ While turning (RH/LH)
Headlight❏ ON / ❏ OFF Rear defogger❏ ON / ❏ OFF
Blower❏ ON / ❏ OFF Audio❏ ON / ❏ OFF
A/C compressor❏ ON / ❏ OFF Car phone❏ ON / ❏ OFF
Radiator fan❏ ON / ❏ OFF
Fr o nt wi pe r❏ ON / ❏ OFF
Rear wiper❏ ON / ❏ OFF

EN(H4SO)-5
ENGINE (DIAGNOSTIC)
Check List for Interview
2. CHECK LIST No. 2
Check the following items about the vehicle’s state when malfunction indicator light turns on.
NOTE:
Use copies of this page for interviewing customers.
a) Other warning lights or indicators turn on. ❏ Yes / ❏ No
❏ Low fuel warning light
❏ Charge indicator light
❏ AT diagnostic indicator light
❏ ABS Warning light
❏ Oil pressure indicator light
b) Fuel level
 Lack of gasoline: ❏ Yes / ❏ No
 Indicator position of fuel gauge:
 Experienced running out of fuel: ❏ Ye s / ❏ No
c) Intentional connecting or disconnecting of harness connectors or spark plug cords: ❏ Yes / ❏ No
 What:
d) Intentional connecting or disconnecting of hoses: ❏ Ye s / ❏ No
 What:
e) Installing of other parts except genuine parts: ❏ Ye s / ❏ No
 What:
 Where:
f) Occurrence of noise: ❏ Yes / ❏ No
From where:
 What kind:
g) Occurrence of smell: ❏ Yes / ❏ No
From where:
 What kind:
h) Intrusion of water into engine compartment or passenger compartment: ❏ Yes / ❏ No
i) Troubles occurred
❏ Engine does not start.
❏ Engine stalls during idling.
❏ Engine stalls while driving.
❏ Engine speed decreases.
❏ Engine speed does not decrease.
❏ Rough idling
❏ Poor acceleration
❏ Back fire
❏ After fire
❏ Does not shift.
❏ Excessive shift shock

EN(H4SO)-7
ENGINE (DIAGNOSTIC)
General Description
 The antenna feeder must be placed as far
apart as possible from the ECM and MFI har-
ness.
 Carefully adjust the antenna for correct
matching.
 When mounting a large power type radio, pay
special attention to the three items above men-
tioned.
 Incorrect installation of the radio may affect
the operation of the ECM.
13) Before disconnecting the fuel hose, disconnect
the fuel pump connector and crank the engine for
more than five seconds to release pressure in the
fuel system. If engine starts during this operation,
run it until it stops.
14) Problems in the electronic-controlled automatic
transmission may be caused by failure of the en-
gine, the electronic control system, the transmis-
sion proper, or by a combination of these. These
three causes must be distinguished clearly when
performing diagnostics.
15) Diagnostics should be conducted by rotating
with simple, easy operations and proceeding to
complicated, difficult operations. The most impor-
tant thing in diagnostics is to understand the cus-
tomer’s complaint, and distinguish between the
three causes.
16) In AT models, do not continue the stall for more
than five seconds. (from closed throttle, fully open
throttle to stall engine speed.)
17) On the model with ABS, when performing driv-
ing test in jacked-up or lifted-up position, some-
times the warning light may be lit, but this is not a
malfunction of the system. The reason for this is the
speed difference between the front and rear
wheels. After diagnosis of engine control system,
perform the ABS memory clearance procedure of
self-diagnosis function.
B: INSPECTION
Before performing diagnostics, check the following
items which might affect engine problems:
1. BATTERY
1) Measure battery voltage and specific gravity of
electrolyte.
Standard voltage: 12 V
Specific gravity: Above 1.260
2) Check the condition of the main and other fuses,
and harnesses and connectors. Also check for
proper grounding.
2. ENGINE GROUND
Make sure the engine grounding terminal is proper-
ly connected to the engine.
C: NOTE
1. GENERAL DESCRIPTION
 On-board diagnosis (OBD) system detects and
indicates a fault in various inputs and outputs of the
complex electronic control. Malfunction indicator
light in the combination meter indicates occurrence
of a fault or trouble.
 Further, against such a failure or sensors as may
disable the drive, the fail-safe function is provided
to ensure the minimal driveability.
 The OBD system incorporated with the vehicles
within this engine family complies with Section
1968.1, California Code of Regulations (OBD-II
regulation). The OBD system monitors the compo-
nents and the system malfunction listed in Engine
Section which affects on emissions.
 When the system decides that a malfunction oc-
curs, malfunction indicator light illuminates. At the
same time of the malfunction indicator light illumi-
nation or blinking, the DTC and a freeze frame en-
gine conditions are stored into on-board computer.
 The OBD system stores freeze frame engine
condition data (engine load, engine coolant tem-
perature, fuel trim, engine speed and vehicle
speed, etc.) into on-board computer when it detects
a malfunction first.
 If the OBD system detects the various malfunc-
tions including the fault of fuel trim or misfire, the
OBD system first stores freeze frame engine condi-
tions about the fuel trim or misfire.
 When the malfunction does not occur again for
three consecutive driving cycles, malfunction indi-
cator light is turned off, but DTC remains at on-
board computer.
 The OBD-II system is capable of communication
with a general scan tool (OBD-II general scan tool)
formed by ISO 9141 CARB.
EN-00153

EN(H4SO)-27
ENGINE (DIAGNOSTIC)
OBD-II General Scan Tool
9. OBD-II General Scan Tool
A: OPERATION
1. HOW TO USE OBD-II GENERAL SCAN
TOOL
1) Prepare a general scan tool (OBD-II general
scan tool) required by SAE J1978.
2) Connect the OBD-II general scan tool to its data
link connector in the lower portion of the instrument
panel (on the driver’s side).3) Using the OBD-II general scan tool, call up the
DTC and freeze frame data.
OBD-II general scan tool functions consist of:
(1) MODE $01: Current powertrain diagnostic
data
(2) MODE $02: Powertrain freeze frame data
(3) MODE $03: Emission-related powertrain
DTC
(4) MODE $04: Clear/Reset emission-related
diagnostic information
Read out data according to repair procedures. (For
detailed operation procedures, refer to the OBD-II
General Scan Tool Operation Manual.)
NOTE:
For details concerning DTCs, refer to the List of Di-
agnostic Trouble Code (DTC). 72, List of Diagnostic Trouble Code (DTC).>
2. MODE $01 (CURRENT POWERTRAIN DIAGNOSTIC DATA)
Refers to data denoting the current operating condition of analog input/output, digital input/output and/or the
powertrain system.
A list of the support data and PID (Parameter Identification) codes are shown in the following table.
NOTE:
Refer to OBD-II general scan tool manufacturer’s instruction manual to access generic OBD-II PIDs (MODE
$01).
ME-00325
PID Data Unit of measure
01 Number of emission-related powertrain DTC and malfunction indicator light status ON/OFF
03 Fuel system control status—
04 Calculated engine load value%
05 Engine coolant temperature°C
06 Short term fuel trim%
07 Long term fuel trim%
0B Intake manifold absolute pressure kPa
0C Engine speedrpm
0D Vehicle speedkm/h
0E Ignition timing advance°
10 Air flow rate of manifold absolute pressure sensor g/sec
11 Throttle valve opening angle%
13 Check whether oxygen sensor is installed. —
14Oxygen sensor output voltage and short term fuel trim — bank 1 associated with oxygen sen-
sorV and%
15Oxygen sensor output voltage and short term fuel trim — bank 2 associated with oxygen sen-
sorV and %
1C On-board diagnostic system—

EN(H4SO)-32
ENGINE (DIAGNOSTIC)
Subaru Select Monitor
5. READ CURRENT DATA FOR ENGINE (OBD MODE)
1) On the «Main Menu» display screen, select the {Each System Check} and press the [YES] key.
2) On the «System Selection Menu» display screen, select the {Engine} and press the [YES] key.
3) Press the [YES] key after the information of engine type was displayed.
4) On the «Engine Diagnosis» display screen, select the {OBD system} and press the [YES] key.
5) On the «OBD Menu» display screen, select the {Current Data Display & Save}, and press the [YES] key.
6) On the «Data Display Menu» display screen, select the {Data Display} and press the [YES] key.
7) Using the scroll key, scroll the display screen up or down until the desired data is shown.
 A list of the support data is shown in the following table.
NOTE:
For detailed operation procedure, refer to the “SUBARU SELECT MONITOR OPERATION MANUAL”.
Description Display Unit of measure
Number of DTC Number of diagnosis code —
Condition of malfunction indicator light MI (MIL) ON or OFF
Monitoring test of misfire Misfire Monitoring Complete or incomplete
Monitoring test of fuel system Fuel System Diagnosis Complete or incomplete
Monitoring test of comprehensive component Component Diagnosis Complete or incomplete
Test of catalyst Catalyst diagnosis Complete or incomplete
Test of heating-type catalyst Heated catalyst diagnosis No support
Test of evaporative emission purge control system Evap. purge diagnosis Complete or incomplete
Test of secondary air system Secondary air diagnosis No support
Test of air conditioning system refrigerant A/C refrigerant diagnosis No support
Test of oxygen sensor O2 sensor diagnosis Complete or incomplete
Test of oxygen sensor heater O2 heater diagnosis Complete or incomplete
Test of EGR system EGR diagnosis —
Air fuel ratio control system for bank 1 Fuel System for bank 1 —
Engine load data Engine load %
Engine coolant temperature signal Engine coolant temperature°C or (°F)
Short term fuel trim by front oxygen (A/F) sensor Short term fuel trim B1 %
Long term fuel trim by front oxygen (A/F) sensor Long term fuel trim B1 %
Intake manifold absolute pressure signalIntake manifold absolute pres-
suremmHg, kPa, inHg or psi
Engine speed signal Engine speed rpm
Vehicle speed signal Meter vehicle speed km/h or MPH
Ignition timing advance for #1 cylinder Ignition timing adv. #1°
Intake air temperature signal Intake air temperature°C or (°F)
Amount of intake air Amount of intake air g/s
Throttle position signal Throttle valve angle %
Rear oxygen sensor output signal O2 sensor #12 V
Air fuel ratio correction by rear oxygen sensor Short term fuel trim #12 %
On-board diagnostic system OBD system —
Oxygen sensor #11 O2 sensor #11 With support
Oxygen sensor #12 O2 sensor #12 With support
A/F sensor #11 A/F sensor #11 —

EN(H4SO)-35
ENGINE (DIAGNOSTIC)
Subaru Select Monitor
8. READ CURRENT DATA FOR AT
1) On the «Main Menu» display screen, select the {Each System Check} and press the [YES] key.
2) On the «System Selection Menu» display screen, select the {Transmission} and press the [YES] key.
3) Press the [YES] key after the information of transmission type is displayed.
4) On the «Transmission Diagnosis» display screen, select the {Current Data Display & Save} and press the
[YES] key.
5) On the «Transmission Diagnosis» display screen, select the {Data Display} and press the [YES] key.
6) Using the scroll key, scroll the display screen up or down until the desired data is shown.
 A list of the support data is shown in the following table.
Description Display Unit of measure
Battery voltage Battery Voltage V
Rear vehicle speed sensor signal Rear Wheel Speed km/h or MPH
Front vehicle speed sensor signal Front Wheel Speed km/h or MPH
Engine speed signal Engine speed rpm
ATF temperature signal ATF Temp.°C or °F
Throttle position sensor Throttle Sensor Voltage V
Gear Position Gear position —
Line pressure control duty ratio Line pressure duty %
Lock up clutch control duty ratio L/U Duty %
Transfer clutch control duty ratio AWD duty %
Throttle position sensor power supply Throttle sensor power supply V
Turbine revolution signal Turbine Revolution Speed rpm
2-4 Brake timing pressure control duty ratio 2-4 B Pressure Duty %
Intake manifold pressure sensor voltage Mani. Relative Voltage V
FWD switch signal FWD SW ON or OFF
Kick down switch signal Kick Down Switch ON or OFF
Stop light switch signal Stop Light SW ON or OFF
Anti lock brake system signal ABS signal ON or OFF
Cruise control system signal Cruise Control Signal ON or OFF
Neutral/Parking range signal N/P range ON or OFF
Reverse range signal R Range ON or OFF
Drive range signal D Range ON or OFF
3rd range signal 3rd Range Signal ON or OFF
2nd range signal 2nd Range Signal ON or OFF
1st range signal 1st Range Signal ON or OFF
Shift control solenoid A Shift Solenoid #1 ON or OFF
Shift control solenoid B Shift Solenoid #2 ON or OFF
Torque control output signal #1 Torque control output signal 1 ON or OFF
Torque control output signal #2 Torque control output signal 2 ON or OFF
Torque control cut signal Torque Control Cut Sig ON or OFF
2-4 brake timing control solenoid valve 2-4B Timing Solenoid ON or OFF
Low clutch timing control solenoid valve L/C timing solenoid ON or OFF
Automatic transmission diagnosis light output signal Diagnosis Lamp ON or OFF

EN(H4SO)-40
ENGINE (DIAGNOSTIC)
Inspection Mode
7) Connect the Subaru Select Monitor to data link
connector.
(1) Connect the Subaru Select Monitor to data
link connector located in the lower portion of the
instrument panel (on the driver’s side).
(2) Connect the diagnosis cable to data link
connector.
CAUTION:
Do not connect the scan tools except for Suba-
ru Select Monitor and OBD-II general scan tool.
8) Turn ignition switch to ON (engine OFF) and turn
Subaru Select Monitor switch to ON.
9) On the «Main Menu» display screen, select the
{Each System Check} and press the [YES] key.
10) On the «System Selection Menu» display
screen, select the {Engine} and press the [YES]
key.
11) Press the [YES] key after the information of en-
gine type was displayed.
12) On the «Engine Diagnosis» screen, select the
{D Check} and press the [YES] key.
13) When the “Perform D Check?” is shown on the
screen, press the [YES] key.
14) Perform subsequent procedures as instructed
on the display screen.
 If trouble still remains in the memory, the corre-
sponding DTC appears on the display screen.
NOTE:
 For detailed operation procedure, refer to the
“SUBARU SELECT MONITOR OPERATION
MANUAL”. For details concerning DTCs, refer to the List of Di-
agnostic Trouble Code (DTC). 72, List of Diagnostic Trouble Code (DTC).>
 Release the parking brake.
 The speed difference between front and rear
wheels may light either the ABS warning light, but
this indicates no malfunctions. When engine con-
trol diagnosis is finished, perform the ABS memory
clearance procedure of self-diagnosis function.
3. OBD-II GENERAL SCAN TOOL
1) After clearing the memory, check for any remain-
ing unresolved trouble data. 44, Clear Memory Mode.>
2) Idle the engine.
3) Connect the test mode connector (A) located at
the lower portion of instrument panel (on the driv-
er’s side).
4) Connect the OBD-II general scan tool to its data
link connector in the lower portion of the instrument
panel lower panel (on the driver’s side).
CAUTION:
Do not connect the scan tools except for Suba-
ru Select Monitor and OBD-II general scan tool.
5) Start the engine.
NOTE:
 Ensure the select lever is placed in the “P” range
before starting. (AT model)
 Depress the clutch pedal when starting the en-
gine. (MT model)
6) Using the selector lever or shift lever, turn the “P”
range switch and the “N” range switch to ON.
(A) Power switch
ME-00325
EN-00040
(A)
EN-00238
(A)
ME-00325