1997 SUBARU LEGACY battery

B2M0526A
8F4CHECK HARNESS BETWEEN FUEL
PUMP AND FUEL PUMP RELAY CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Measure resistance of harness connector between fuel
pump and fuel pump relay.
: Connector & terminal
(R58) No. 1—(B46) No. 4:
Is the resistance less than 1Ω?
: Go to next.
: Repair open circuit in harness between fuel pump
and fuel pump relay connector.
: Connector & terminal
(R58) No. 1—Chassis ground:
Is the resistance more than 1 MΩ?
: Go to step8F5.
: Repair short circuit in harness between fuel pump
and fuel pump relay connector.
G2M0461
8F5
CHECK FUEL PUMP RELAY.
1) Disconnect connectors from fuel pump relay and main
relay.
2) Remove fuel pump relay and main relay with bracket.
3) Connect battery to fuel pump relay connector terminals
No. 1 and No. 3.
4) Measure resistance between connector terminals of
fuel pump relay.
: Terminals
No. 2—No. 4:
Is the resistance less than 10Ω?
: Go to step8F6.
: Replace fuel pump relay.
11 8
2-7ON-BOARD DIAGNOSTICS II SYSTEM
8. Diagnostics for Engine Starting Failure

B2M0481
10D2CHECK HARNESS BETWEEN ECM AND
MASS AIR FLOW SENSOR CONNECTOR.
1) Turn ignition switch to OFF and Subaru Select Monitor
or the OBD-II general scan tool switch to OFF.
2) Disconnect connector from mass air flow sensor.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Read data on Subaru select monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F06
: Is the value more than 250 g/sec or5Vin
function mode F06?
: Repair battery short circuit in harness between
mass air flow sensor and ECM connector. After
repair, replace ECM.
: Replace mass air flow sensor.

OBD-II general scan tool
For detailed operation procedures, refer to OBD-II General
Scan Tool Instruction Manual.
140
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0756
10G4CHECK HARNESS BETWEEN ECM AND
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF and Subaru Select Monitor
or the OBD-II general scan tool switch to OFF.
2) Disconnect connector from pressure sensor.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Read data on Subaru select monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F21
: Is the value more than 140 kPa in function
mode F21?
: Repair battery short circuit in harness between
ECM and pressure sensor connector.
: Replace pressure sensor.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
153
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0145A
10I1CONNECT 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.
B2M0479
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F04

F04: Water temperature is indicated in“°C”and“°F”.
: Is the value less than40°Cor40°Fin
function mode F04?
: Go to step10I3.
: Repair poor contact.
NOTE:
In this case, repair the following:

Poor contact in engine coolant temperature sensor

Poor contact in ECM

Poor contact in coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0618A
10I2CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
OBD0696A
4) Measure voltage between engine coolant temperature
sensor connector and engine ground.
: Connector & terminal
(E8) No. 1 (+)—Engine ground ():
Is the voltage more than 10 V?
: Repair battery short circuit in harness between
ECM and engine coolant temperature sensor con-
nector.
: Go to next step 5).
158
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0696A
5) Turn ignition switch to ON.
6) Measure voltage between engine coolant temperature
sensor connector and engine ground.
: Connector & terminal
(E8) No. 1 (+)—Engine ground ():
Is the voltage more than 10 V?
: Repair battery short circuit in harness between
ECM and engine coolant temperature sensor con-
nector.
: Go to step10I3.
OBD0696A
10I3CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
1) Measure voltage between engine coolant temperature
sensor connector and engine ground.
: Connector & terminal
(E8) No. 1 (+)—Engine ground ():
Is the voltage more than 4 V?
: Go to next step 2).
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and engine cool-
ant temperature sensor connector

Poor contact in engine coolant temperature sensor con-
nector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
OBD0697A
2) Turn ignition switch to OFF.
3) Measure resistance of harness between engine coolant
temperature sensor connector and engine ground.
: Connector & terminal
(E8) No. 2—Engine ground:
Is the resistance less than 5Ω?
: Replace engine coolant temperature sensor.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and engine cool-
ant temperature sensor connector

Poor contact in engine coolant temperature sensor con-
nector

Poor contact in ECM connector

Poor contact in coupling connector (B21)
159
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0703A
10L2CHECK HARNESS BETWEEN THROTTLE
POSITION SENSOR AND BODY CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from throttle position sensor.
3) Measure resistance of harness between throttle posi-
tion sensor connector and engine ground.
: Connector & terminal
(E13) No. 1—Engine ground:
Is the resistance less than 5Ω?
: Go to next step 4).
: Repair open circuit in harness between throttle
position sensor and ECM connector.
OBD0704A
4) Turn ignition switch to ON.
5) Measure voltage between throttle position sensor con-
nector and engine ground.
: Connector & terminal
(E13) No. 2 (+)—Engine ground ():
Is the voltage more than 4.9 V?
: Repair battery short circuit in harness between
throttle position sensor and ECM connector. After
repair, replace ECM.
: Replace throttle position sensor.
169
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

NOTE:
In this case, repair the following:

Poor contact in front oxygen sensor connector

Poor contact in ECM connector
: Go to step10P3.

OBD-II scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M0548A
10P3CHECK OUTPUT SIGNAL FROM ECM.
(USING VOLTAGE METER.)
1) Start and idle the engine.
2) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 38 (+)—Chassis ground ():
Is the voltage less than 1.0 V?
: Go to step10P4.
: Go to next.
: Does the voltage change less than 1.0 V by
shaking harness and connector of ECM
while monitoring the value with voltage
meter?
: Repair poor contact in ECM connector.
: Go to next step 3).
B2M0548A
3) Disconnect connector from front oxygen sensor.
4) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 38 (+)—Chassis ground ():
Is the voltage less than 1.0 V?
: Replace ECM.
: Repair battery short circuit in harness between
ECM and front oxygen sensor connector. After
repair, replace ECM.
B2M1075A
10P4CHECK POWER SUPPLY TO FRONT
OXYGEN SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from front oxygen sensor.
3) Turn ignition switch to ON.
4) Measure voltage between front oxygen sensor connec-
tor and engine ground.
: Connector & terminal
(B18) No. 2 (+)—Engine ground ():
Is the voltage more than 10 V?
179
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

NOTE:
In this case, repair the following:

Poor contact in rear oxygen sensor connector

Poor contact in rear oxygen sensor connecting harness
connector

Poor contact in ECM connector
: Go to step10S3.

OBD-II scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
B2M0554A
10S3CHECK OUTPUT SIGNAL FROM ECM.
(USING VOLTAGE METER.)
1) Start and idle the engine.
2) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 37 (+)—Chassis ground ():
Is the voltage less than 1.0 V?
: Go to step10S4.
: Go to next.
: Does the voltage change less than 1.0 V by
shaking harness and connector of ECM
while monitoring the value with voltage
meter?
: Repair poor contact in ECM connector.
: Go to next step 3).
B2M0554A
3) Disconnect connector from rear oxygen sensor.
4) Measure voltage between ECM connector and chassis
ground.
: Connector & terminal
(B84) No. 37 (+)—Chassis ground ():
Is the voltage less than 1.0 V?
: Replace ECM.
: Repair battery short circuit in harness between
ECM and rear oxygen sensor connector. After
repair, replace ECM.
OBD0710C
10S4CHECK POWER SUPPLY TO REAR OXY-
GEN SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from rear oxygen sensor.
3) Turn ignition switch to ON.
4) Measure voltage between rear oxygen sensor connec-
tor and engine ground or chassis ground.
: Connector & terminal

2200 cc California spec. vehicles
(B19) No. 2 (+)—Engine ground ():
188
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles