2004 SUBARU FORESTER sensor

EN(H4DOTC)-6
ENGINE (DIAGNOSTIC)
General Description
3. General Description
A: CAUTION
1) Airbag system wiring harness is routed near the
ECM, main relay and fuel pump relay.
CAUTION:
 All airbag system wiring harness and con-
nectors are all colored yellow.Do not use the
electrical test equipment on these circuits.
 Be careful not to damage the Airbag system
wiring harness when servicing the ECM, TCM,
main relay and fuel pump relay.
2) Never connect the battery in reverse polarity.
 The ECM will be destroyed immediately.
 The fuel injector and other part will be damaged.
3) Do not disconnect the battery terminals while the
engine is running.
 A large counter electromotive force will be gener-
ated in the generator, and this voltage may damage
electronic parts such as ECM, etc.
4) Before disconnecting the connectors of each
sensor and the ECM, be sure to turn OFF the igni-
tion switch.
5) Poor contact has been identified as a primary
cause of this problem.Measure the voltage or resis-
tance of individual sensor or all electrical control
modules using a tapered pin with a diameter of less
than 0.64 mm (0.025 in).Do not insert the pin more
than 5 mm (0.20 in) into the part.
6) Remove the ECM from the located position after
disconnecting two cables on battery.
 Otherwise, the ECM may be damaged.
CAUTION:
When replacing the ECM, be careful not to use
the wrong spec. ECM to avoid damaging the
fuel injection system.
7) Connectors to each sensor in the engine com-
partment and the harness connectors on the en-
gine side and body side are all designed to be
waterproof.However, take care not to allow water to
get into the connectors when washing the vehicle,
or when servicing the vehicle on a rainy day. 8) Use ECM mounting stud bolts on the body
grounding point when measuring voltage and resis-
tance inside the passenger compartment.
9) Use engine ground terminal or engine proper as
the grounding point to the body when measuring
voltage and resistance in the engine compartment.
10) Use TCM mounting stud bolts on the grounding
point when measuring voltage and resistance in-
side the passenger compartment.
11) Every MFI-related part is a precision part.Do
not drop them.
(A) Stud bolt
(A) Stud bolt
EN-00069
(A)
EN-00070
EN-00071(A)

EN(H4DOTC)-7
ENGINE (DIAGNOSTIC)
General Description
12) Observe the following cautions when installing
a radio in MFI equipped models.
CAUTION:
 The antenna must be kept as far apart as pos-
sible from the control unit. (The ECM is located
under the steering column, inside of the instru-
ment panel lower trim panel.)
 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 (engine, electronic control system,
transmission) 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) 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 1.2602) 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 ground terminal is properly
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-00070

EN(H4DOTC)-11
ENGINE (DIAGNOSTIC)
Electrical Component Location
 SENSOR
(1) Manifold absolute pressure sensor (4) Knock sensor (7) Mass air flow and intake air tem-
perature sensor
(2) Engine coolant temperature sen-
sor(5) Camshaft position sensor
(6) Crankshaft position sensor (8) Tumble generator valve position
sensor (3) Throttle position sensor
EN-00293
(1)
(7) (6) (4) (8) (5)(2)
(3)

EN(H4DOTC)-13
ENGINE (DIAGNOSTIC)
Electrical Component Location
(1) Front oxygen (A/F) sensor (3) Exhaust gas temperature sensor (5) Rear Oxygen Sensor
(2) Precatalytic converter (4) Front catalytic converter (6) Rear catalytic converter
(1)
(4) (3)
(5)(6)
(2)
EN-00302

EN(H4DOTC)-15
ENGINE (DIAGNOSTIC)
Electrical Component Location
 LHD MODEL
 RHD MODEL
(1) Fuel level sensor (2) Fuel sub level sensor
EN-00308(2)
(1)
EN-00309(2)
(1)
EN-00310 (1)EN-00311 (2)

EN(H4DOTC)-21
ENGINE (DIAGNOSTIC)
Electrical Component Location
 SENSOR
(1) Rear vehicle speed sensor (AT
model)(3) Front vehicle speed sensor (AT
model)(5) ATF temperature sensor (AT
model)
(2) Front vehicle speed sensor (MT
model)(4) Torque converter turbine speed
sensor (AT model)(6) Brake light switch
(1)EN-00327(2)EN-00328
EN-00184 (3)
(1)EN-00107 (2)
EN-00186 (2)EN-00187(5)
EN-00188 (6)

EN(H4DOTC)-23
ENGINE (DIAGNOSTIC)
Engine Control Module (ECM) I/O Signal
5. Engine Control Module (ECM) I/O Signal
A: ELECTRICAL SPECIFICATION
DESCRIPTION Connector No. Terminal No.Signal (V)
NOTE
Ignition SW ON
(engine OFF)Engine ON
(Idling)
Crank-
shaft posi-
tion sensorSignal (+) B135 10 0−7 — +7 Waveform
Signal (−) B135 22 0 0 —
Shield B135 31 0 0 —
Camshaft
position
sensorSignal (+) B135 11 0−7 — +7 Waveform
Signal (−) B135 23 0 0 —
Shield B135 31 0 0 —
Throttle
position
sensorSignal B136 18Fully closed: 0.2 — 1.0
Fully opened: 4.2 — 4.7—
Pow er
supplyB136 16 5 5 —
GND
(sensors)B136 35 0 0 —
Rear Oxy-
gen Sen-
sorSignal B137 25 0 0 — 0.9 —
Shield B137 31 0 0 —
GND
(sensors)B136 35 0 0 —
Fr o nt ox y-
gen (A/F)
sensor
heaterSignal 1 B134 3 0 — 1.0 0 — 1.0 Waveform
Signal 2 B134 2 0 — 1.0 0 — 1.0 Waveform
Rear oxygen sensor
heater signalB135 2 0 — 1.0 0 — 1.0 Waveform
Engine
coolant
tempera-
ture sen-
sorSignal B136 14 1.0 — 1.4 1.0 — 1.4 After engine is warmed-up.
GND
(sensors)B136 35 0 0 After engine is warmed-up.
Vehicle speed signal B135 26 0 or 5 0 or 5“5” and “0” are repeatedly dis-
played when vehicle is driven.
EN-02308
B134
34
3330 31 3229 26
27
28 25
1
2
8 9 310
11 12
19 20 21 13 14
15
16 17
18 22 23 24
3330 31 32
29 26
27
28 25
7
8 9 5 64
10
11 12
19 20 21 13 14
15 16
17
18 22
23 241
2 3
7 5 64
3534
B137 B135
B136
33
30 31
32
29 26
27
28 25
8 910
11 12
19
20 21 13 14
15 16 17
18
22
23 241
2
3
75 64
3534
30 3129
26
27
28 25
8 910
11 12
19 20 21 13 14
15 16 17
18 22
23 241 2
3
75 64

EN(H4DOTC)-24
ENGINE (DIAGNOSTIC)
Engine Control Module (ECM) I/O Signal
AV C S
camshaft
position
sensor RHSignal (+) B135 21 0−7 — +7 Waveform
Signal (−) B135 29 0 0 —
Shield B135 30 0 0 —
AV C S
camshaft
position
sensor LHSignal (+) B135 20 0−7 — +7 Waveform
Signal (−) B135 28 0 0 —
Shield B135 30 0 0 —
Generator signal B134 22ON: 1, or less
OFF: 10 — 13ON: 1, or less
OFF: 10 — 13Wavefor m
Air flow
sensorSignal B136 23 — 0.3 — 4.5 —
Shield B136 32 0 0 —
GND B136 31 0 0 —
Intake air temperature
sensor signalB136 13 0.3 — 4.6 0.3 — 4.6 —
Exhaust
gas tem-
perature
sensorSignal B136 24 — — —
GND
(sensor)B136 35 0 0 —
Tu m b l e
generator
valve posi-
tion sen-
sor RHSignal B136 27Fully closed: 3.8 — 4.9
Fully opened: 0.2 — 0.9—
Pow er
supplyB136 16 5 5 —
GND
(sensor)B136 35 0 0 —
Tu m b l e
generator
valve posi-
tion sen-
sor LHSignal B136 26Fully closed: 3.8 — 4.9
Fully opened: 0.2 — 0.9—
Pow er
supplyB136 16 5 5 —
GND
(sensor)B136 35 0 0 —
Tumble generator valve
RH (open)B134 9 0 or 10 — 13 0 or 13 — 14 Waveform
Tumble generator valve
RH (close)B134 8 0 or 10 — 13 0 or 13 — 14 Waveform
Tumble generator valve
LH (open)B134 11 0 or 10 — 13 0 or 13 — 14 Waveform
Tumble generator valve
LH (close)B134 10 0 or 10 — 13 0 or 13 — 14 Waveform
Wastegate control sole-
noid valveB134 32 0 or 10 — 13 0 or 13 — 14 —
Starter switch B137 8 0 0 Cranking: 8 — 14
A/C switch B137 17ON: 10 — 13
OFF: 0ON: 13 — 14
OFF: 0—
Ignition switch B137 14 10 — 13 13 — 14 —
Neutral Position Switch B137 9ON: 12±0.5
OFF: 0Switch is ON when gear is in
neutral position.
Test Mode Connector B137 15 10 — 13 13 — 14 When connected: 0
Knock
sensorSignal B136 25 2.8 2.8 —
Shield B136 33 0 0 —
Back-up power supply B135 19 10 — 13 13 — 14 Ignition switch “OFF”: 10 — 13
Control module power
supplyB135 5 10 — 13 13 — 14 —
B135 6 10 — 13 13 — 14 — DESCRIPTION Connector No. Terminal No.Signal (V)
NOTE
Ignition SW ON
(engine OFF)Engine ON
(Idling)