check engine light SUBARU LEGACY 1997 Service Service Manual

6. Basic Diagnostic Procedure
Trouble occurs.
Ask the customer when and how the
trouble occurred using interview
check list.
Start the engine.
Ye sNoInspection using“8. Diagnostics for
Engine Start Failure”. [T800].>
Malfunction indicator lamp (MIL) illu-
minates.
Ye sNoInspection using“9. General Diag-
nostics Table”.
Inspection using Subaru select moni-
tor or OBD-II general scan tool.
(Subaru select monitor: MODE FB1)
Trouble code
No trouble code designated.Repair.
See NOTE: *1
designated.
Inspection using“10. Diagnostics
Chart with Trouble Code for LHD
Vehicles”.
“11. Diagnostics Chart with Trouble
Code for RHD Vehicles”. [T1100].>
See NOTE: *2.
Trouble code
designated.

Repair.
Inspection mode
Inspection using Subaru select moni-
tor or OBD-II general scan tool.
(Subaru select monitor: MODE FB0)
No trouble code
Clear memory mode.
designated.
END
NOTE:

*1: If trouble code is not shown on display although the
MIL illuminates, perform diagnostics of the MIL (CHECK
ENGINE LIGHT) circuit or combination meter. [T700].>

*2: Carry out the basic check, only when trouble code
about automatic transmission is shown on display. 2-7 [T6A0].>






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2-7ON-BOARD DIAGNOSTICS II SYSTEM
6. Basic Diagnostic Procedure

B: CHECK LIST FOR INTERVIEW
1. CHECK LIST NO. 1
Check the following items when problem has occurred.
NOTE:
Use copies of this page for interviewing customers.
Customer’s name Engine no.
Date of sale Fuel brand
Date of repair Odometer reading km
Vin no.miles
WeatherFine
Cloudy
Rainy
Snowy
Various/Others:
Outdoor temperature F(°C)
Hot
Warm
Cool
Cold
PlaceHighway
Suburbs
Inner city
Uphill
Downhill
Rough road
Others:
Engine temperatureCold
Warming-up
After warming-up
Any temperature
Others:
Engine speed rpm
Vehicle speed MPH
Driving conditionsNot affected
At starting
While idling
At racing
While accelerating
While cruising
While decelerating
While turning (RH/LH)
HeadlightON/OFF Rear defoggerON/OFF
BlowerON/OFF RadioON/OFF
A/C compressorON/OFF CD/CassetteON/OFF
Cooling fanON/OFF Car phoneON/OFF
Front wiperON/OFF CBON/OFF
Rear wiperON/OFF
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
6. Basic Diagnostic Procedure

2. CHECK LIST NO. 2
Check the following items about the vehicle’s state when
MIL turns on.
NOTE:
Use copies of this page for interviewing customers.
a) Other warning lights or indicators turn on.Yes/No
Low fuel warning light
Charge indicator light
AT diagnostics indicator light
ABS warning light
TCS warning light
Engine oil pressure warning light
b) Fuel level

Lack of gasoline:Yes/No

Indicator position of fuel gauge:
c) Intentional connecting or disconnecting of harness connectors or spark plug cords:Yes/No

What:
d) Intentional connecting or disconnecting of hoses:Yes/No

What:
e) Installing of parts other than genuine parts:Yes/No

What:

Where:
f) Occurrence of noise:Yes/No

From where:

What kind:
g) Occurrence of smell:Yes/No

From where:

What kind:
h) Intrusion of water into engine compartment or passenger compartment:Yes/No
i) Troubles occurred
Engine does not start.
Engine stalls during idling.
Engine stalls while driving.
Engine speed decreases.
Engine speed does not decrease.
Rough idling
Poor acceleration
Back fire
After fire
No shift
Excessive shift shock
87
2-7ON-BOARD DIAGNOSTICS II SYSTEM
6. Basic Diagnostic Procedure

OBD0145A
10F1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Start engine.
B2M0756
5) Read the data on Subaru Select Monitor or the OBD-II
general scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21

F21: Display shows pressure signal value sent from
pressure sensor.
: Is the value less than 0 kPa in function
mode F21?
: Go to step10F2.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M0535A
10F2CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 21 (+)—Chassis ground ():
Is the voltage more than 4.5 V?
: Go to next step 2).
: Go to next.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0145A
10V1CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Start engine.
H2M1308
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F44

F44: Fuel temperature is indicated in“°C”and“°F”.
: Is the value greater than 150°Cor300°Fin
function mode F44?
: Go to step10V2.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
G2M0340
10V2CHECK HARNESS BETWEEN FUEL TEM-
PERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Remove access hole lid.
3) Disconnect connector from fuel pump.
OBD0145A
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
5) Turn ignition switch and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
198
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1090
10AJ3
CHECK KNOCK SENSOR.
1) Disconnect connector from knock sensor.
2) Measure resistance between knock sensor connector
terminal and engine ground.
: Terminal
No. 2—Engine ground:
Is the resistance less than 400 kΩ?
: Replace knock sensor.
: Repair ground short circuit in harness between
knock sensor connector and ECM connector.
NOTE:
The harness between both connectors is shielded. Repair
short circuit of harness together with shield.
B2M0561A
10AJ4
CHECK INPUT SIGNAL FOR ECM.
1) Connect connectors to ECM and knock sensor.
2) Turn ignition switch to ON.
3) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 3 (+)—Chassis ground ():
Is the voltage more than 2 V?
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. (However, the pos-
sibility of poor contact still remains.)
NOTE:
In this case, repair the following:

Poor contact in knock sensor connector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
: Repair poor contact in ECM connector.
221
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AP1
CHECK ENGINE/TRANSMISSION TYPE.
: Is engine/transmission type 2200 cc/MT?
: Check AT/MT identification circuit. [T10DD0].>
: Go to step10AP2.
B2M0566A
10AP2
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 71 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Go to next.
: Go to step10AP3.
: Is there poor contact in ECM connector?
: Repair poor contact in ECM connector.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. (However, the pos-
sibility of poor contact still remains.)
NOTE:
In this case, repair the following:

Poor contact in EGR solenoid valve connector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
OBD0678A
10AP3CHECK HARNESS BETWEEN EGR
SOLENOID VALVE AND ECM CONNEC-
TOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from EGR solenoid valve and
ECM.
3) Measure resistance of harness between EGR solenoid
valve connector and engine ground.
: Connector & terminal
(E18) No. 2—Engine ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and EGR solenoid valve connector.
: Go to next step 4).
238
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0570A
10AT1
CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chassis ground.
: Connector & terminal
(B84) No. 72 (+)—Chassis ground ():
Is the voltage more than 10 V?
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. Contact with SOA
service.
NOTE:
Inspection by DTM is required, because probable cause is
deterioration of multiple parts.
: Go to step10AT2.
OBD0680A
10AT2CHECK HARNESS BETWEEN PURGE
CONTROL SOLENOID VALVE AND ECM
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from purge control solenoid
valve and ECM.
3) Measure resistance of harness between purge control
solenoid valve connector and engine ground.
: Connector & terminal
(E4) No. 2—Engine ground:
Is the resistance less than 10Ω?
: Repair ground short circuit in harness between
ECM and purge control solenoid valve connector.
: Go to next step 4).
B2M0571A
4) Measure resistance of harness between ECM and
purge control solenoid valve of harness connector.
: Connector & terminal
(B84) No. 72—(E4) No. 2:
Is the resistance less than 1Ω?
: Go to step10AT3.
: Repair open circuit in harness between ECM and
purge control solenoid valve connector.
249
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

H2M1414B
10AZ3CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Turn ignition switch to ON. (Engine OFF)
2) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 27 (+)—Chassis ground ():
Is the voltage less than 0.12 V?
: Go to step10AZ4.
: Go to next.
H2M1327
: Does the value change less than 0.12 V by
shaking harness and connector of ECM
while monitoring the value with Subaru
Select Monitor?

Subaru Select Monitor
Designate mode using function key.
Function mode: F45

F45: Fuel level sensor output signal is indicated.
: Repair poor contact in ECM connector.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. A temporary poor
contact of the connector may be the cause.
NOTE:
In this case, repair the following:

Poor contact in fuel pump connector

Poor contact in combination meter connector

Poor contact in ECM connector

Poor contact in coupling connector (i3, B99, B22, B98
and R57)
G2M0340
10AZ4CHECK HARNESS BETWEEN ECM, COM-
BINATION METER AND FUEL PUMP
CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove fuel pump access hole lid located on the right
rear of trunk compartment floor (Sedan) or luggage com-
partment floor (Wagon).
271
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

H2M1414B
10BA3CHECK INPUT SIGNAL FOR ECM.
(USING VOLTAGE METER AND SUBARU
SELECT MONITOR.)
1) Turn ignition switch to ON. (Engine OFF)
2) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 27 (+)—Chassis ground ():
Is the voltage more than 4.75 V?
: Go to step10BA4.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. A temporary poor
contact of the connector may be the cause.
NOTE:
In this case, repair the following:

Poor contact in fuel pump connector

Poor contact in combination meter connector

Poor contact in ECM connector

Poor contact in coupling connector (i3, B99, B22, B98
and R57)
G2M0340
10BA4
CHECK FUEL LEVEL SENSOR.
1) Turn ignition switch to OFF.
2) Remove fuel pump access hole lid located on the right
rear of trunk compartment floor (Sedan) or luggage com-
partment floor (Wagon).
B2M0935
3) Disconnect connector from fuel pump.
4) Measure resistance between connector terminals of
fuel pump.
: Terminals
No. 3—No. 5:
Is the resistance less than 100Ω?
: Go to step10BA5.
: Replace fuel sending unit.
G2M0863
10BA5
CHECK FUEL SUB LEVEL SENSOR.
1) Remove service hole cover located on the left rear of
trunk compartment floor (Sedan) or luggage compartment
floor (Wagon).
277
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles