2004 SUBARU FORESTER transmission

EN(H4SO)-25
ENGINE (DIAGNOSTIC)
Transmission Control Module (TCM) I/O Signal
7. Transmission Control Module (TCM) I/O Signal
A: ELECTRICAL SPECIFICATION
For the electrical specification of TCM I/O signal, refer to 4AT(H4SO) section. ELECTRICAL SPECIFICATION, Transmission Control Module (TCM) I/O Signal.>

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)-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)-59
ENGINE (DIAGNOSTIC)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK BATTERY.
Check the battery voltage.Is the voltage more than 12 V? Go to step 2.Charge or replace
the battery.
2 CHECK INPUT SIGNAL FOR STARTER MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from starter
motor.
3) Turn the ignition switch to START.
4) Measure the power supply voltage between
starter motor connector terminal and engine
ground.
Connector & terminal
(B14) No. 1 (+) — Engine ground (
−):
N
OTE:
 For AT model, shift the select lever to “P” or
“N” range.
 For MT model, depress the clutch pedal.Is the voltage more than 10 V? Go to step 3.Go to step 4.
3 CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the ground cable terminal from
starter motor.
3) Measure the resistance of ground cable
between ground cable terminal and engine
ground.Is the resistance less than 5
Ω?Check the starter
motor. SC(H4SO)-6,
Starter.>Repair open circuit
of ground cable.
4 CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1) Disconnect the connector from ignition
switch.
2) Measure the power supply voltage between
ignition switch connector and chassis ground.
Connector & terminal
(B72) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 5.Repair open circuit
in harness
between ignition
switch and bat-
tery, and check
fuse SBF No. 4
and SBF No. 1.
5 CHECK IGNITION SWITCH.
1) Disconnect the connector from ignition
switch.
2) Measure the resistance between ignition
switch terminals while turning the ignition
switch to START position.
Te r m i n a l s
No. 1 — No. 3:Is the resistance less than 5
Ω?Go to step 6.Replace the igni-
tion switch.
6 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 7.Temporary poor
contact occurs.
Check poor con-
tact in each con-
nectors.
7 CHECK INHIBITOR SWITCH INPUT VOLT-
AGE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from inhibitor
switch.
3) Connect the connector to ignition switch.
4) Measure the input voltage between inhibitor
switch connector terminal and engine ground
while turning the ignition switch to START posi-
tion.
Connector & terminal
(B12) No. 12 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 8.Repair open or
ground short cir-
cuit in harness
between inhibitor
switch and ignition
switch.
N
OTE:
Check security sys-
tem (if equipped).

EN(H4SO)-74
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P0420 Catalyst System Efficiency Below
Threshold (Bank 1) BELOW THRESHOLD (BANK 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0458 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit Low TROL SYSTEM PURGE CONTROL VALVE CIRCUIT LOW, Diagnostic Pro-
cedure with Diagnostic Trouble Code (DTC).>
P0459 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit High TROL SYSTEM PURGE CONTROL VALVE CIRCUIT HIGH, Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0461 Fuel Level Sensor Circuit Range/Per-
formance RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0462 Fuel Level Sensor Circuit Low Input INPUT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0463 Fuel Level Sensor Circuit High Input HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0464 Fuel Level Sensor Circuit Intermittent INTERMITTENT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0483 Cooling Fan Rationality Check CHECK, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0502 Vehicle Speed Sensor Circuit Low
Input LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0503 Vehicle Speed Sensor Intermittent/
Erratic/High HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0506 Idle Control System RPM Lower
Than Expected LOWER THAN EXPECTED, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0507 Idle Control System RPM Higher
Than Expected HIGHER THAN EXPECTED, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0512 Starter Request Circuit nostic Procedure with Diagnostic Trouble Code (DTC).>
P0513 Incorrect Immobilizer Key Procedure with Diagnostic Trouble Code (DTC).>
P0519 Idle Control System Malfunction
(Fail-Safe) TION (FAIL-SAFE), Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0565 Cruise Control On Signal Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0604 Internal Control Module Random
Access Memory (RAM) Error READ ACCESS MEMORY (RAM) ERROR, Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0691 Cooling Fan 1 Control Circuit Low LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0692 Cooling Fan 1 Control Circuit High HIGH, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0703 Torque Converter/Brake Switch “B”
Circuit SWITCH “B” CIRCUIT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0705 Transmission Range Sensor Circuit
(PRNDL Input) dure without Diagnostic Trouble Code (DTC).>
P0710 Transmission Fluid Temperature
Sensor Circuit tic Procedure with Diagnostic Trouble Code (DTC).>
P0716 Torque converter turbine speed sen-
sor SENSOR, Diagnostic Procedure with Diagnostic Trouble Code (DTC).> DTC Item NOTE

EN(H4SO)-186
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK TRANSMISSION TYPE.Is the transmission type AT? Go to step 2.Go to step 3.
2 CHECK DTC P0720 ON DISPLAY.Does the Subaru Select Moni-
tor or OBD-II general scan tool
indicate DTC P0720?Check front vehi-
cle speed sensor
signal circuit.
4AT(H4SO)-45,
DTC 33 FRONT
VEHICLE SPEED
SENSOR, Diag-
nostic Procedure
with Diagnostic
Trouble Code
(DTC).>Go to step 3.
3 CHECK SPEEDOMETER OPERATION IN
COMBINATION METER.Does speedometer operate
normally?Go to step 4.Check speedome-
ter and vehicle
speed sensor.
Speedometer.>
Front Vehicle
Speed Sensor.>
Rear Vehicle
Speed Sensor.>
Torque Converter
Turbine Speed
Sensor.>
4 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the combi-
nation meter.
3) Measure the resistance between ECM and
combination meter connector.
Connector & terminal
(B137) No. 10 — (i10) No. 12:Is the resistance less than 10
Ω?Repair the poor
contact in ECM
connector.Repair harness
and connector.
NOTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and combi-
nation meter con-
nector
 Poor contact in
ECM connector.
 Poor contact in
combination meter
connector
 Poor contact in
coupling connector

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)-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).>