SUBARU FORESTER 1999 Service Manual Online

D: SCHEMATIC
S6M0390
19
[T3D0]6-2DIAGNOSTICS
3. Cruise Control System

E: CONTROL MODULE I/O SIGNAL
G6M0015
Content Terminal No. Measuring conditions and I/O signals (ignition switch ON and engine idling)
Vent valve 1IPower supply is ON when vehicle is stopped.
ION-and-OFF (ª0º-and-battery voltage) operation is alternately repeated while
cruise control is operating.
Safety valve 2IPower supply is ON when vehicle is stopped.
ION-and-OFF (ª0º-and-battery voltage) operation is alternately repeated while
cruise control is operating.
Ignition switch 3IBattery voltage is present when ignition switch is turned ON.
Iª0º volt is present when ignition switch is turned OFF.
Cruise control main switch 4IBattery voltage is present when main power is turned ON.
Iª0º volt is present when main power is turned OFF.
Power supply to vacuum valve,
vent valve, safety valve and
indicator light5IBattery voltage is present when main power is turned ON.
Iª0º volt is present when main power is turned OFF.
SET/COAST switch 6IBattery voltage is present when command switch is turned to SET/COAST
position.
Iª0º volt is present when command switch is released.
RESUME/ACCEL switch 7IBattery voltage is present when command switch is turned to RESUME/
ACCEL position.
Iª0º volt is present when command switch is released.
Brake switch 8 Set select lever to any position other than ªPº or ªNº position (AT) / leave
clutch pedal released (MT), while cruise control main switch is turned ON.
Then check that;
IBattery voltage is present when brake pedal is released.
Iª0º volt is present when brake pedal is depressed, or
IBattery voltage is present when clutch pedal is released (MT).
Iª0º volt is present when clutch pedal is depressed (MT).
IBattery voltage is present when select lever is in any position other than ªPº
or ªNº position (AT).
Iª0º volt is present when select lever is set to ªPº or ªNº position (AT).
Clutch switch (MT)/
Inhibitor switch (AT)9IBattery voltage is present when clutch pedal is released (MT).
Iª0º volt is present when clutch pedal is depressed (MT).
IBattery voltage is present when select lever is in any position other than ªPº
or ªNº position (AT).
Iª0º volt is present when select lever is set to ªPº or ªNº position (AT).
Vacuum valve 11IPower supply is ON when vehicle is stopped.
ION-and-OFF (ª0º-and-battery voltage) operation is alternately repeated while
cruise control is operating.
Set signal to transmission con-
trol module (AT)12ITCM emits a ground-level signal while driving vehicle at least 40 km/h (25
MPH) with SET switch ON.
Ground 13 Ð
Check connector/
OBD-II service connector14 Ð
Check connector/
OBD-II service connector15 Ð
20
6-2[T3E0]DIAGNOSTICS
3. Cruise Control System

Content Terminal No. Measuring conditions and I/O signals (ignition switch ON and engine idling)
Vehicle speed sensor (MT)
Automatic transmission control
module (AT)18 Lift-up the vehicle until all four wheels are raised off ground, and then rotate
any wheel manually. Approx. 5 and 0 volt pulse signals are alternately input to
cruise control module.
Stop light switch 19 Turn ignition switch to OFF. Then check that;
IBattery voltage is present when brake pedal is depressed.
Iª0º volt is present when brake pedal is released.
Ground 20 Ð
NOTE:
Voltage at terminals 1, 2, 11 and 12 cannot be checked unless vehicle is driving by cruise control operation.
21
[T3E0]6-2DIAGNOSTICS
3. Cruise Control System

F: DIAGNOSTICS CHART FOR ON-
BOARD DIAGNOSIS SYSTEM
1. BASIC DIAGNOSTIC PROCEDURE
3F11 : CHECK CRUISE CONTROL MAIN
SWITCH.
1) Trouble occurs.
2) Perform pre-inspection.
3) Check cruise control main switch.
:Does cruise control main switch turn
ON?
: Go to step3F12.
: Go to ªDiagnostics Chart for Power
Lineº.
3F12 : CHECK CRUISE SPEED IS SET.
:Does cruise speed properly set while
driving at minimum of 40 km/h (25
MPH)?
: Go to step3F13.
: Go to ªDiagnostics Chart with Trouble
Codeº.
3F13 : CHECK CRUISE CONTROL IS
RELEASED.
:Does cruise control properly release
during operation?
: Go to step3F14.
: Go to ªDiagnostics Chart with Trouble
Codeº.
3F14 : CHECK CRUISE SPEED IS HELD
WITHIN SET SPEED.
:Does cruise speed hold within set
speed
±3 km/h (2 MPH)?
: Go to step3F15.
: Go to pre-inspection of actuator. to 6-2 [T3B4].>
3F15 : CHECK RESUME/ACCEL SWITCH.
:Does RESUME/ACCEL switch func-
tion properly?
: Go to step3F16.
: Go to ªDiagnostics Chart with Trouble
Codeº. 3F16 : CHECK SET/COAST SWITCH.
:Does SET/COAST switch function
properly?
: Go to step3F17.
: Go to ªDiagnostics Chart with Trouble
Codeº.
3F17 : CHECK CANCEL SWITCH.
:Does CANCEL switch function prop-
erly?
: Go to step3F18.
: Go to ªDiagnostics Chart with Trouble
Codeº.
3F18 : CHECK CRUISE SPEED IS
RELEASED.
:Does cruise speed release when
brake pedal is depressed?
: Go to step3F19.
: Go to ªDiagnostics Chart with Trouble
Codeº.
3F19 : CHECK CRUISE SPEED IS
RELEASED.
:Does cruise speed release when
clutch pedal is depressed?
: Cruise control system is in correct order.
: Go to ªDiagnostics Chart with Trouble
Codeº.
22
6-2[T3F1]DIAGNOSTICS
3. Cruise Control System

2. ON-BOARD DIAGNOSIS WITH SELECT
MONITOR
IGeneral
The on-board diagnosis function of the cruise con-
trol system uses an external select monitor.
The on-board diagnosis function operates in two
categories, which are used depending on the type
of problems;
NOTE:
Select monitor part No.:

1) Cruise cancel conditions diagnosis
(1) This category of diagnosis requires actual
vehicle driving in order to determine the cause,
(as when cruise speed is cancelled during driv-
ing although cruise cancel condition is not
entered).
(2) Cruise control module memory stores the
cancel condition (Code No.) which occurred
during driving. When there are plural cancel
conditions (Code No.), they are shown on the
select monitor.
CAUTION:
IThe cruise control memory stores not only
the cruise ªcancelº which occurred (although
ªcancelº operation is not entered by the
driver), but also the ªcancelº condition input by
the driver.
IThe content of memory is cleared when igni-
tion switch or cruise main switch is turned OFF.
2) Real-time diagnosis
The real-time diagnosis function is used to deter-
mine whether or not the input signal system is in
good order, according to signal emitted from
switches, sensors, etc.
(1) Vehicle cannot be driven at cruise speed
because problems occurs in the cruise control
system or its associated circuits.
(2) Monitor the signal conditions from switches
and sensors.
ICruise Cancel Conditions Diagnosis
1) Connect select monitor.
2) Start the engine and turn cruise control main
switch to ON.
3) Set select monitor in ªAll System Diagnosisº
mode.
NOTE:
The diagnostic code is also shown in the ªEach
System Checkº mode. This mode is called up on
the ªCruise Control Diagnosisº screen by selecting
the item ªCancel Code(s) Displayº.
4) Drive vehicle at least 40 km/h (25 MPH) with
cruise speed set.5) If cruise speed is canceled itself (without doing
any cancel operations), a diagnostic code will
appear on select monitor display.
CAUTION:
IA diagnostic code will also appear when
cruise cancel is effected by driver. Do not con-
fuse.
IHave a co-worker ride in vehicle to assist in
diagnosis during driving.
NOTE:
Diagnostic code will be cleared by turning ignition
switch or cruise control main switch to OFF.
IReal-Time Diagnosis
1) Connect select monitor.
2) Turn ignition switch and cruise control main
switch to ON.
3) Select the ªCurrent Data Display & Saveº mode
on the select monitor ªCruise Control Diagnosisº
screen.
4) Ensure that normal indication is displayed when
controls are operated as indicated below:
IDepress/release the brake pedal. (Stop light
switch and brake switch turn ON.)
ITurn ON the ªSET/COASTº switch.
ITurn ON the ªRESUME/ACCELº switch.
IDepress/release the clutch pedal. (MT)
ISet the select lever to P or N. (AT)
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[T3F2]6-2DIAGNOSTICS
3. Cruise Control System

G: DIAGNOSTICS CHART FOR
POWER LINE
1. BASIC DIAGNOSTICS PROCEDURE
3G11 : DRIVE AT CRUISE SPEED.
:Can cruise speed be set?
: Go to ªCHECK INDICATOR AND CIR-
CUIT IN CRUISE CONTROL MAIN
SWITCHº.
: Go to ªCHECK CRUISE CONTROL
MAIN SWITCHº.
2. CHECK INDICATOR AND CIRCUIT IN CRUISE CONTROL MAIN SWITCH
DIAGNOSIS:
IBulb failure or open harness of the indicator circuit in the cruise control main switch.
TROUBLE SYMPTOM:
ICruise control can be set, normally indicator does not come on. (When main switch is pressed.)
WIRING DIAGRAM:
S6M0108
24
6-2[T3G1]DIAGNOSTICS
3. Cruise Control System

3G21 : CHECK CRUISE CONTROL MAIN
SWITCH.
1) Remove cruise control main switch.
2) Measure resistance between cruise control
main switch terminals.
Terminals
No. 1 Ð No. 6:
S6M0109A
:Is resistance between 10 and 80W?
: Go to step3G22.
: Replace switch illumination bulb. to 6-2 [W12B2].>
3G22 : CHECK CIRCUIT BETWEEN CRUISE
CONTROL MODULE AND CRUISE
CONTROL MAIN SWITCH INDICA-
TOR LIGHT.
1) Turn the ignition switch to ON.
2) Turn cruise control main switch to ON.
3) Measure voltage between cruise control main
switch connector and the chassis ground.
Connector & terminal
(B161) No. 1 (+) Ð Chassis ground (þ):
B6M0528B
:Is voltage more than 10 V?
: Go to step3G23.
: Repair or replace wiring harness.3G23 : CHECK CIRCUIT BETWEEN CRUISE
CONTROL MODULE AND CRUISE
CONTROL MAIN SWITCH INDICA-
TOR LIGHT.
1) Turn the ignition switch and cruise control main
switch to OFF.
2) Remove the connector from the cruise control
main switch.
3) Measure resistance of ground circuit between
the cruise control main switch connector and chas-
sis ground.
Connector & terminal
(B161) No. 6 (+) Ð Chassis ground (þ):
B6M0531B
:Is resistance less than 10W?
: Replace cruise control module. 6-2 [W12B4].>
: Repair or replace wiring harness.
25
[T3G2]6-2DIAGNOSTICS
3. Cruise Control System

3. CHECK CRUISE CONTROL MAIN SWITCH
DIAGNOSIS:
IFaulty cruise control main switch, or open harness.
TROUBLE SYMPTOM:
ICruise control main switch is not turned ON and cruise control cannot be set.
NOTE:
When the main relay (built-in cruise control module) operates, the main switch circuit is in normal condi-
tion.
The main relay operation can be checked by hearing the operation sounds.
This operation sounds will be heard when ignition switch and cruise control main switch is turned to ON.
WIRING DIAGRAM:
S6M0108
26
6-2[T3G3]DIAGNOSTICS
3. Cruise Control System

3G31 : CHECK FUSE.
Check fuse No. 18.
S6M0110A
:Is fuse No. 18 blown?
: Replace fuse No. 18. Go to step3G32.
: Go to step3G32.
3G32 : CHECK POWER SUPPLY.
1) Turn ignition switch to ON.
2) Measure voltage between fuse & relay box con-
nector and chassis ground.
Connector & terminal
(B152) No. 5 (+) Ð Chassis ground (þ):
:Is voltage more than 10 V?
: Go to step3G33.
: Replace fuse No. 18. When fuse No. 18
is blown again, repair shorted parts of
circuit.3G33 : CHECK CRUISE CONTROL MAIN
SWITCH.
1) Turn ignition switch to OFF.
2) Remove cruise control main switch and discon-
nect connector.
3) Turn ignition switch to ON.
4) Measure voltage between cruise control main
switch connector and chassis ground.
Connector & terminal
(B161) No. 3 (+) Ð Chassis ground (þ):
B6M0183C
:Is voltage more than 10 V?
: Go to step3G34.
: Replace cruise control main switch.

3G34 : CHECK CRUISE CONTROL MAIN
SWITCH.
Measure resistance between cruise control main
switch terminals.
Terminals
No. 3 Ð No. 5:
G6M0244
:Is resistance less than 10W? (When
switch is ON.)
: Go to step3G35.
: Replace cruise control main switch.

27
[T3G3]6-2DIAGNOSTICS
3. Cruise Control System

3G35 : CHECK CRUISE CONTROL MAIN
SWITCH.
Measure resistance between cruise control main
switch terminals.
Terminals
No. 3 Ð No. 5:
G6M0244
:Is resistance less than 1 MW? (When
switch is OFF.)
: Go to step3G36.
: Replace cruise control main switch.

3G36 : CHECK HARNESS BETWEEN
CRUISE CONTROL MAIN SWITCH
CONNECTOR AND CHASSIS
GROUND.
1) Connect connector.
2) Turn ignition switch to ON.
3) Turn cruise control main switch to ON.
4) Measure voltage between terminal of cruise
control main switch and chassis ground.
Connector & terminal
(B161) No. 3 (+) Ð Chassis ground (þ):
S6M0111A
:Is voltage more than 10 V?
: Go to step3G37.
: Repair or replace wiring harness.3G37 : CHECK HARNESS BETWEEN
CRUISE CONTROL MAIN SWITCH
CONNECTOR AND CHASSIS
GROUND.
Measure voltage between terminal of cruise con-
trol main switch chassis ground.
Connector & terminal
(B161) No. 5 (+) Ð Chassis ground (þ):
S6M0111A
:Is voltage more than 10 V?
: Go to step3G38.
: Repair or replace wiring harness.
3G38 : CHECK HARNESS BETWEEN
CRUISE CONTROL MODULE CON-
NECTOR AND CHASSIS GROUND.
Measure voltage between terminal of cruise con-
trol module and chassis ground.
Connector & terminal
(B94) No. 4 (+) Ð Chassis ground (þ):
S6M0111A
:Is voltage more than 10 V?
: Replace cruise control module. 6-2 [W12B4].>
: Repair or replace wiring harness.
NOTE:
Depress cruise control main switch with fingers
while measuring voltage between (B161) No. 5
and chassis ground.
28
6-2[T3G3]DIAGNOSTICS
3. Cruise Control System