2004 SUBARU FORESTER coolant temperature

EN(H4DOTC 2.5)-117
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR
1) Start and warm-up the engine until engine
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in neutral position.
3) Turn the A/C switch to OFF.
4) Turn all accessory switches to OFF.
5) Open the hood.
6) Measure the ambient temperature.
7) Read the data of mass air flow and intake
air temperature sensor signal using Subaru
Select Monitor or the 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”. 2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Subtract the ambient tempera-
ture from intake air tempera-
ture, and is the value −10 —
50°C (14 — 122°F)?Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.Check mass air
flow and intake air
temperature sen-
sor. FU(H4DOTC 2.5)-
30, Mass Air Flow
and Intake Air
Temperature Sen-
sor.> Step Check Yes No

EN(H4DOTC 2.5)-258
ENGINE (DIAGNOSTIC)
General Diagnostic Table
19.General Diagnostic Table
A: INSPECTION
1. ENGINE
NOTE:
Malfunction of parts other than those listed is also possible. General.>
Symptom Problem parts
1. Engine stalls during idling.1) Electronic throttle control
2) Manifold absolute pressure sensor
3) Mass air flow and intake air temperature sensor
4) Ignition parts (*1)
5) Engine coolant temperature sensor (*2)
6) Crankshaft position sensor (*3)
7) Camshaft position sensor (*3)
8) Fuel injection parts (*4)
2. Rough idling1) Electronic throttle control
2) Manifold absolute pressure sensor
3) Mass air flow and intake air temperature sensor
4) Engine coolant temperature sensor (*2)
5) Ignition parts (*1)
6) Air intake system (*5)
7) Fuel injection parts (*4)
8) Crankshaft position sensor (*3)
9) Camshaft position sensor (*3)
10) Oxygen sensor
11) Fuel pump and fuel pump relay
3. Engine does not return to idle.1) Electronic throttle control
2) Engine coolant temperature sensor
3) Manifold absolute pressure sensor
4) Mass air flow sensor
4. Poor acceleration1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Electronic throttle control
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
6) Engine coolant temperature sensor (*2)
7) Crankshaft position sensor (*3)
8) Camshaft position sensor (*3)
9) A/C switch and A/C cut relay
10) Engine torque control signal circuit
11) Ignition parts (*1)
5. Engine stalls or engine sags or hesitates at
acceleration.1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Purge control solenoid valve
7) Fuel injection parts (*4)
8) Fuel pump and fuel pump relay
6. Surging1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Fuel injection parts (*4)
7) Throttle position sensor
8) Fuel pump and fuel pump relay

EN(H4DOTC 2.5)-259
ENGINE (DIAGNOSTIC)
General Diagnostic Table
*1: Check ignition coil & ignitor ASSY and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Ensure the secure installation.
*4: Check fuel injector, fuel pressure regulator and fuel filter.
*5: Inspect air leak in air intake system. 7. Spark knock1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor
4) Knock sensor
5) Fuel injection parts (*4)
6) Fuel pump and fuel pump relay
8. After burning in exhaust system1) Manifold absolute pressure sensor
2) Mass air flow and intake air temperature sensor
3) Engine coolant temperature sensor (*2)
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay Symptom Problem parts

4AT-33
AUTOMATIC TRANSMISSION
Stall Test
5. Stall Test
A: INSPECTION
NOTE:
The stall test is of extreme importance in diagnos-
ing the condition of the automatic transmission and
the engine. It should be conducted to measure the
engine stall speeds in “R” and “2” ranges (when
HOLD switch is ON).
Purposes of the stall test:
 To check the operation of the automatic trans-
mission clutch.
 To check the operation of the torque converter
clutch.
 To check engine performance.
1) Check that the throttle valve opens fully.
2) Check that the engine oil level is correct.
3) Check that the coolant level is correct.
4) Check that the ATF level is correct.
5) Check that the differential gear oil level is cor-
rect.
6) Increase ATF temperature to 70 — 80°C (158 —
176°F) by idling the engine for approximately 30
minutes (with select lever set to “N” or “P”).
7) Place the wheel chocks at the front and rear of
all wheels and engage the parking brake.
8) Shift the manual linkage to ensure it operates
properly, then shift the select lever to the “2” range
and turn the HOLD switch to ON.
9) While forcibly depressing the foot brake pedal,
gradually depress the accelerator pedal until the
engine operates at full throttle.
10) When the engine speed is stabilized, record
that speed quickly and release the accelerator ped-
al.
11) Shift the select lever to “N” range, and cool
down the engine by idling it for more than one
minute.12) If the stall speed in “2” range (with HOLD switch
ON) is higher than specifications, low clutch slip-
ping and “2-4 brake slipping” may occur. To identify
it, conduct the same test as above in “R” range.
13) Perform the stall tests with the select lever in
the “D” range.
NOTE:
 Do not continue the stall test for more than five
seconds at a time (from closed throttle, fully open
throttle to stall speed reading). Failure to follow this
instruction causes the engine oil and ATF to deteri-
orate and the clutch and brake to be adversely af-
fected.
 Be sure to cool down the engine for at least one
minute after each stall test with the select lever set
in the “P” or “N” range and with the idle speed lower
than 1,200 rpm.
 If the stall speed is higher than the specified
range, attempt to finish the stall test in as short a
time as possible, in order to prevent the automatic
transmission from sustaining damage.
Stall speed (at sea level):
2.0 L NON-TURBO MODEL
2,000 — 2,500 rpm
2.0 L TURBO MODEL
2,600 — 3,300 rpm
2.5 L NON-TURBO MODEL
2,100 — 2,600 rpm
2.5 L TURBO MODEL
2,700 — 3,200 rpm
(A) Brake pedal
(B) Accelerator pedal
(A) (B)
P
R
N
D
3
2
1
AT-00449

4AT(H4SO)-37
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM and
ECM.
3) Measure the resistance of harness
between TCM and ECM connector.
Connector & terminal
(B55) No. 17 — (B134) No. 10:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
ECM connector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM connector and chassis ground.
Connector & terminal
(B55) No. 17 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 3.Repair the short
circuit in harness
between TCM and
ECM connector.
3 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 5.Go to step 4.
4 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and ECM.
2) Turn the ignition switch to ON (engine
OFF).
3) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B55) No. 17 (+) — Chassis ground (
−):Is the voltage more than 10.5
V?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and ECM.Go to step 6.
5 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine and turn Subaru Select
Monitor switch to ON.
4) Warm-up the engine until engine coolant
temperature is above 80°C (176°F).
5) Idle the engine.
6) Read the data of engine speed using Sub-
aru Select Monitor.
 Display shows the engine speed signal value
sent from ECM.Is the revolution value same as
tachometer reading shown on
combination meter?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and ECM.Go to step 6.
6 CHECK POOR CONTACT.Is there poor contact in engine
speed signal circuit?Repair the poor
contact.Go to step 7.
7 CONFIRM DTC 11.Replace the ECM with a new
one. Does the DTC 11 appear
again, after memory has been
cleared?Replace the TCM.
Transmission Con-
trol Module
(TCM).>Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>

4AT(H4SO)-55
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
5 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and ECM.
2) Start the engine, and warm-up the trans-
mission until ATF temperature is above 80°C
(176°F).
N
OTE:
If ambient temperature is below 0°C (32°F),
drive the vehicle until ATF reaches its operating
temperature.
3) Idle the engine.
4) Measure the voltage between TCM con-
nector and chassis ground.
Connector & terminal
(B54) No. 1 (+) — Chassis ground (
−):Is the voltage 0.4 — 1.6 V? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and ECM.Go to step 7.
6 CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine, and turn Subaru Select
Monitor switch to ON.
4) Warm-up the engine until engine coolant
temperature is above 80°C (176°F).
5) Idle the engine.
6) Read the data of intake manifold pressure
signal using Subaru Select Monitor.
 Display shows the intake manifold pressure
signal value sent from ECM.Is the voltage 0.4 — 1.6 V? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and ECM.Go to step 7.
7 CHECK POOR CONTACT.Is there poor contact in intake
manifold pressure signal cir-
cuit?Repair the poor
contact.Replace the TCM.
Transmission Con-
trol Module
(TCM).> Step Check Yes No