1999 SUBARU FORESTER check engine light

4. Diagnostics Chart for On-
board Diagnostic System
A: BASIC DIAGNOSTICS
PROCEDURE
4A1 : CHECK AIRBAG WARNING LIGHT
ILLUMINATES.
1) Turn ignition switch to ON (engine OFF).
2) Check airbag warning light illuminates.
:Does airbag warning light stay ON
after about 7 seconds or remain OFF,
or come back ON after 30 seconds?
: Repair and replace. [T4D0].>
: Go to step4A2.
4A2 : CHECK TROUBLE CODE INDICATES.
Perform ON-BOARD DIAGNOSTICS. [T4B0].>
:Does trouble code indicate? 5-5 [T5A0].>
: Repair and replace. [T5X0].> Go to step4A3.
: Repair and replace. [T5Y0].> Go to step4A3.
4A3 : CHECK AIRBAG WARNING LIGHT
ILLUMINATES.
1) Turn ignition switch to ON (engine OFF).
2) Check airbag warning light illuminates.
:Does airbag warning light stay ON
after about 7 seconds or come back
ON after 30 seconds?
: Repair and replace. [T4D0].>
: Go to step4A4.4A4 : CHECK AIRBAG WARNING LIGHT
ILLUMINATES.
Check airbag warning light illuminates.
:Does airbag warning light come ON
for about 7 seconds, then go out and
stay out?
: Perform clear memory. [T4C0].>
: Go to step4A1.
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition,
the airbag warning light will remain on for about 7
seconds and go out when the ignition switch is set
to ON.
If there is any malfunction, the airbag warning light
will either stay on or off continuously. In such
cases, perform on-board diagnostic in accordance
with the specified procedure to determine trouble
codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal to No. 1 terminal of
diagnosis connector located inside lower cover.
B5M0115D
3) Check in accordance with the trouble code indi-
cated by the AIRBAG warning light, and record the
trouble codes.
4) Turn the ignition switch ªOFFº and remove the
DIAG. terminal from No. 1 terminal of diagnosis
connector.
11
[T4B0]5-5DIAGNOSTICS
4. Diagnostics Chart for On-board Diagnostic System

C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
1) Make sure ignition switch is ON (and engine
off). Connect one DIAG. terminal ªAº on diagnosis
connector terminal No. 1.
While warning light is flashing, contact the other
DIAG. terminal ªBº on terminal No. 2 for at least
three seconds.
B5M0116D
2) After memory is cleared, normal warning light
flashing rate resumes. (Warning light flashes every
0.6 seconds ON-OFF operation.) Memory cannot
be cleared if any problem exists.
3) After clear memory and then DIAG. terminals
ªAº and ªBº, extract from diagnosis connector.
D: DIAGNOSTICS PROCEDURE
4D1 : CHECK TROUBLE CODE INDICATES.
1) Perform on-board diagnostic. [T4B0].>
2) Check trouble code indicates.
:Are trouble codes 11, 12, 15 or 16
indicated?
: Go to step4D2.
: Perform diagnostics and repair accord-
ing to indicated trouble code. 5-5 [T5A0].>
4D2 : CHECK TROUBLE CODE INDICATES.
Check trouble code indicates.
:Are trouble codes 12, 16 indicated?

: Go to step4D3.
: Go to step4D4.
12
5-5[T4C0]DIAGNOSTICS
4. Diagnostics Chart for On-board Diagnostic System

5V2 : INSPECTION OF AIRBAG WARNING
LIGHT
1) Turn ignition switch ªOFFº and connect body
harness connector (B31) to test connector A con-
nector (1A).
S5M0282A
2) Connect battery ground cable and turn ignition
switch ªONº, (engine off) and connect connectors
(3A) and (4A).
G5M0455
:Does the airbag warning light come
off?
: Go to step5V4.
: Go to step5V3.5V3 : INSPECTION OF BODY HARNESS
Check body harness.
NOTE:
After problem has been eliminated, disconnect
connectors (3A) and (4A).
S5M0283A
:Is there anything unusual to body
harness?
: Repair body harness.
: Replace airbag warning light bulb to 6-2 [W8B0].> or combination meter
printed circuit.
5V4 : CHECK POOR CONTACT IN CON-
NECTOR (AB6).
Check connector (AB6) connected to airbag con-
trol module.
:Is there poor contact in connector
(AB6)?
: Repair poor contact in connector (AB6).
: Go to step5V5.
56
5-5[T5V2]DIAGNOSTICS
5. Diagnostics Chart with Trouble Code

5V8 : INSPECTION OF AIRBAG MAIN HAR-
NESS
1) Connect connectors (AB1) and (B31). Discon-
nect connector (AB6) from airbag control module
, and connect it to test har-
ness I or I2 connector (1I).
2) Measure resistance between each test harness
I or I2 connector (2I) terminal and chassis ground.
Connector & terminal
(2I) No. 9 (+) Ð Chassis ground (þ):
S5M0271B
:Is resistance less than 10W?
: Go to step5V9.
: Replace airbag main harness. 5-5 [W4A0].>
5V9 : INSPECTION OF AIRBAG MAIN HAR-
NESS
Measure resistance between each test harness I
or I2 connector (2I) terminal and chassis ground.
Connector & terminal
(2I) No. 10 (+) Ð Chassis ground (þ):
S5M0272B
:Is resistance less than 10W?
: Replace airbag control module. 5-5 [W6A0].>
: Replace airbag main harness. 5-5 [W4A0].>
W: AIRBAG WARNING LIGHT
REMAINS OFF.
DIAGNOSIS:
IFuse No. 5 (in main fuse box) is blown.
IBody harness circuit is open.
IAirbag warning light is faulty.
IAirbag main harness is faulty.
IAirbag control module is faulty.
CAUTION:
Before performing diagnostics on airbag
system, turn ignition switch ªOFFº, disconnect
battery ground terminal, and then wait at least
20 seconds.
5W1 : FUSE NO. 5 (IN MAIN FUSE BOX)
INSPECTION
Remove and visually check fuse No. 5 (In main
fuse box).
S5M0273A
:Is fuse No. 5 blown?
: Replace fuse No. 5. If fuse No. 5 blows
again, Go to step5W2.
: Go to step5W2.
5W2 : BODY HARNESS INSPECTION
Turn ignition switch ªONº (engine off) to make sure
other warning lights (in combination meter) illumi-
nate.
:Do all the warning lights (in combina-
tion meter) except airbag warning
light come on?
: Go to step5W3.
: Repair body harness.
58
5-5[T5V8]DIAGNOSTICS
5. Diagnostics Chart with Trouble Code

5Y7 : WARNING LIGHT ILLUMINATION
CHECK
Turn ignition switch ªONº (engine off) and observe
airbag warning light.
:Does the airbag warning light come
on for about 7 seconds, then go out
and stay out?
: Perform clear memory. [T4C0].>
: Go to ªDIAGNOSTICS PROCEDUREº.

63
[T5Y7]5-5DIAGNOSTICS
5. Diagnostics Chart with Trouble Code

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

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)
23
[T3F2]6-2DIAGNOSTICS
3. Cruise Control System