2004 SUBARU FORESTER ABS

EN(H4SO)-37
ENGINE (DIAGNOSTIC)
Inspection Mode
12.Inspection Mode
A: OPERATION
Perform the diagnosis on the “Diagnosis Trouble Codes (DTC) List” below.
Refer to the item of drive cycle when perform the diagnosis not on the “Diagnosis Trouble Codes (DTC) List”
below.
DTC Item
P0030 HO2S Heater Control Circuit (Bank 1 Sensor 1)
P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
P0032 HO2S Heater Control Circuit High (Bank 1 Sensor 1)
P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0038 HO2S Heater Control Circuit High (Bank 1 Sensor 2)
P0068 Manifold Pressure Sensor Range/Performance
P0107 Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input
P0112 Intake Air Temperature Circuit Low Input
P0113 Intake Air Temperature Circuit High Input
P0117 Engine Coolant Temperature Circuit Low Input
P0118 Engine Coolant Temperature Circuit High Input
P0122 Throttle/Pedal Position Sensor/Switch “A” Circuit Low Input
P0123 Throttle/Pedal Position Sensor/Switch “A” Circuit High Input
P0129 Barometric Pressure Too Low
P0131 O
2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
P0132 O
2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
P0134 O
2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
P0137 O
2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
P0138 O
2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0335 Crankshaft Position Sensor “A” Circuit
P0336 Crankshaft Position Sensor “A” Circuit Range/Performance
P0340 Camshaft Position Sensor “A” Circuit (Bank 1 or Single Sensor)
P0341 Camshaft Position Sensor “A” Circuit Range/Performance (Bank 1 or Single Sensor)
P0458 Evaporative Emission Control System Purge Control Valve Circuit Low
P0462 Fuel Level Sensor Circuit Low Input
P0463 Fuel Level Sensor Circuit High Input
P0502 Vehicle Speed Sensor Circuit Low Input
P0503 Vehicle Speed Sensor Intermittent/Erratic/High
P0512 Starter Request Circuit
P0513 Incorrect Immobilizer Key
P0519 Idle Control System Malfunction (Fail-Safe)
P0565 Cruise Control On Signal
P0604 Internal Control Module Random Access Memory (RAM) Error
P0703 Torque Converter/Brake Switch “B” Circuit
P0705 Transmission Range Sensor Circuit (PRNDL Input)
P0710 Transmission Fluid Temperature Sensor Circuit
P0716 Torque converter turbine speed sensor
P0720 AT Vehicle Speed Sensor Circuit Malfunction
P0726 Engine Speed Input Circuit Malfunction
P0731 Gear 1 Incorrect Ratio
P0732 Gear 2 Incorrect Ratio
P0733 Gear 3 Incorrect Ratio

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

EN(H4SO)-41
ENGINE (DIAGNOSTIC)
Inspection Mode
7) Depress the brake pedal to turn the brake switch
ON. (AT model)
8) Keep the engine speed in the 2,500 — 3,000
rpm range for 40 seconds.
9) Place the select lever or shift lever in the “D”
range (AT model) or “1st” gear (MT model) and
drive the vehicle at 5 to 10 km/h (3 to 6 MPH).
NOTE:
 On AWD vehicles, 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 system.
10) Using the OBD-II general scan tool, check
DTC(s) and record the result(s).
NOTE:
 For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.
 For details concerning DTCs, refer to the List of Di-
agnostic Trouble Code (DTC). 72, List of Diagnostic Trouble Code (DTC).>

EN(H4SO)-72
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
18.List of Diagnostic Trouble Code (DTC)
A: LIST
DTC Item NOTE
P0030 HO2S Heater Control Circuit (Bank 1
Sensor 1) (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0031 HO2S Heater Control Circuit Low
(Bank 1 Sensor 1) LOW (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0032 HO2S Heater Control Circuit High
(Bank 1 Sensor 1) HIGH (BANK 1 SENSOR 1), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0037 HO2S Heater Control Circuit Low
(Bank 1 Sensor 2) LOW (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0038 HO2S Heater Control Circuit High
(Bank 1 Sensor 2) HIGH (BANK 1 SENSOR 2), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0068 Manifold Pressure Sensor Range/
Pe r fo r ma nc e RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0107 Manifold Absolute Pressure/Baro-
metric Pressure Circuit Low Input BAROMETRIC PRESSURE CIRCUIT LOW INPUT, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P0108 Manifold Absolute Pressure/Baro-
metric Pressure Circuit High Input BAROMETRIC PRESSURE CIRCUIT HIGH INPUT, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P0111 Intake Air Temperature Circuit
Range/Performance RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0112 Intake Air Temperature Circuit Low
Input CUIT LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0113 Intake Air Temperature Circuit High
Input CUIT HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0117 Engine Coolant Temperature Circuit
Low Input CIRCUIT LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0118 Engine Coolant Temperature Circuit
High Input CIRCUIT HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0121 Throttle/Pedal Position Sensor/
Switch “A” Circuit Range/Perfor-
mance SOR/SWITCH “A” CIRCUIT RANGE/PERFORMANCE, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0122 Throttle/Pedal Position Sensor/
Switch “A” Circuit Low Input SOR/SWITCH “A” CIRCUIT LOW INPUT, Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0123 Throttle/Pedal Position Sensor/
Switch “A” Circuit High Input SOR/SWITCH “A” CIRCUIT HIGH INPUT, Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0125 Insufficient Coolant Temperature For
Closed Loop Fuel Control ATURE FOR CLOSED LOOP FUEL CONTROL, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0129 Barometric Pressure Too Low LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

EN(H4SO)-91
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).>Go to step 2.
2 CHECK AIR INTAKE SYSTEM.Are there holes, loose bolts or
disconnection of hose on air
intake system?Repair air intake
system.Go to step 3.
3 CHECK PRESSURE SENSOR.
1) Start and warm-up the engine until engine
coolant temperature is greater than 60°C
(140°F).
2) Shift the select lever in the “P” or “N” range.
3) Turn the A/C switch to OFF.
4) Turn all accessory switches to OFF.
5) Read the data of manifold absolute pres-
sure sensor signal using Subaru Select Moni-
tor or OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the measured value at Igni-
tion ON: 73.3 — 106.6 kPa
(550 — 800 mmHg, 21.65 —
31.50 inHg) Idling: 20.0 — 46.7
kPa (150 — 310 mmHg, 5.91
— 12.20 inHg)?Go to step 4.Replace the mani-
fold absolute pres-
sure sensor. to FU(H4SO)-31,
Manifold Absolute
Pressure Sensor.>
4 CHECK THROTTLE POSITION.
Read the data of throttle position signal using
Subaru Select Monitor or OBD-II general scan
tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the value less than 5% when
the throttle fully closed?Go to step 5.Adjust or replace
the throttle posi-
tion sensor. to FU(H4SO)-29,
Throttle Position
Sensor.>
5 CHECK THROTTLE POSITION.Is the value more than 85%
when the throttle fully opens?Replace the mani-
fold absolute pres-
sure sensor. to FU(H4SO)-31,
Manifold Absolute
Pressure Sensor.>Replace the throt-
tle position sen-
sor. FU(H4SO)-29,
Throttle Position
Sensor.>

EN(H4SO)-92
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
G: DTC P0107 MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE
CIRCUIT LOW INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
193
15
PRESSURE
SENSOR
9
15 12B22
E3
123E21
E21
ECM
B22
125678
131415169101112
34
17181920
B135
B122
1
2
132
EN-02386
B135
567
82 1
94
310
24 22 23 251112131415
26 27
281617181920 21
B122 : LHD
12345678
B122 : RHD
1234

EN(H4SO)-93
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 intake manifold absolute
pressure signal using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II Scan Tool Instruction Manual.Is the value less than 13.3 kPa
(100 mmHg, 3.94 inHg)?Go to step 3.Go to step 2.
2 CHECK POOR CONTACT.
Check poor contact in ECM and manifold pres-
sure sensor connector.Is there poor contact in ECM or
manifold pressure sensor con-
nector?Repair poor con-
tact in ECM or
manifold pressure
sensor connector.Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.
3 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground (
−):Is the voltage more than 4.5 V? Go to step 5.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground (
−):Is the voltage more than 4.5 V
by shaking the ECM harness
and connector?Repair the poor
contact in ECM
connector.Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required,
because probable
cause is deteriora-
tion of multiple
parts.
5 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B135) No. 15 (+) — Chassis ground (
−):Is the voltage less than 0.2 V? Go to step 7.Go to step 6.
6 CHECK INPUT SIGNAL FOR ECM (WITH
SUBARU SELECT MONITOR).
Read the data of barometric absolute pressure
signal using Subaru Select Monitor or OBD-II
general scan tool.
NOTE:
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. to EN(H4SO)-29, Subaru Select Monitor.>Is the value more than 13.3
kPa (100 mmHg, 3.94 inHg)
when shaking the ECM har-
ness and connector?Repair the poor
contact in ECM
connector.Go to step 7.

EN(H4SO)-94
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 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 8.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
8 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
(B135) No. 19 — (E20) No. 1:Is the resistance less than 1
Ω?Go to step 9.Repair the open
circuit in harness
between ECM and
manifold absolute
pressure sensor
connector.
9 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(H4SO)-31,
Manifold Absolute
Pressure Sensor.> Step Check Yes No