check engine SUBARU TRIBECA 2009 1.G Service Workshop Manual

EN(H6DO)(diag)-68
Diagnostics for Engine Starting Failure
ENGINE (DIAGNOSTICS)
2CHECK POWER SUPPLY TO EACH FUEL
INJECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
fuel injector terminal and engine ground.
Connector & terminal
#1 (E5) No. 2 (+) — Engine ground (–):
#2 (E16) No. 2 (+) — Engine ground (–):
#3 (E6) No. 2 (+) — Engine ground (–):
#4 (E17) No. 2 (+) — Engine ground (–):
#5 (E43) No. 2 (+) — Engine ground (–):
#6 (E44) No. 2 (+) — Engine ground (–):
Is the voltage more than 10 V? Go to step 3.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween main re-
lay and fuel
injector connec-
tor
•Poor contact
of main relay
connector
•Poor contact
of coupling con-
nector
•Poor contact
of fuel injector
connector
3CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness
between ECM and fuel injector connector.
Connector & terminal
#1 (B137) No. 8 — (E5) No. 1:
#2 (B137) No. 9 — (E16) No. 1:
#3 (B137) No. 10 — (E6) No. 1:
#4 (B137) No. 11 — (E17) No. 1:
#5 (B137) No. 12 — (E43) No. 1:
#6 (B137) No. 13 — (E44) No. 1:
Is the resistance less than 1
Ω?
Go to step 4.Repair the har-
ness and connec-
tor.
NOTE:In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
fuel injector
connector
•Poor contact
of coupling con-
nector
4CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
#1 (B137) No. 8 — Chassis ground:
#2 (B137) No. 9 — Chassis ground:
#3 (B137) No. 10 — Chassis ground:
#4 (B137) No. 11 — Chassis ground:
#5 (B137) No. 12 — Chassis ground:
#6 (B137) No. 13 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 5.Repair the ground
short circuit of har-
ness between
ECM and fuel
injector connector.
5CHECK EACH FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between each fuel
injector terminals.
Te r m i n a l s
No. 1 — No. 2:
Is the resistance between 5 —
20 Ω?
Go to step 6.Replace the faulty
fuel injector.
6CHECK POOR CONTACT.
Check poor contact of ECM connector.
Is there poor contact in ECM
connector?
Repair poor con-
tact in ECM con-
nector.
Inspection using
“General Diagnos-
tic Table” <Ref. to
EN(H6DO)(diag)-
392, INSPEC-
TION, General
Diagnostic Table.>
Step Check Yes No

EN(H6DO)(diag)-73
List of Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
P0345 Camshaft Position Sensor “A” Circuit
(Bank 2)
<Ref. to EN(H6DO)(diag)-265, DTC P0345 CAMSHAFT POSITION SEN-
SOR “A”CIRCUIT (BANK 2), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0420 Catalyst System Efficiency Below
Threshold (Bank 1)
<Ref. to EN(H6DO)(diag)-267, DTC P0420 CATALYST SYSTEM EFFI-
CIENCY BELOW THRESHOLD (BANK 1), Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0442 Evaporative Emission Control Sys-
tem Leak Detected (Small Leak)
<Ref. to EN(H6DO)(diag)-270, DTC P0442 EVAPORATIVE EMISSION
CONTROL SYSTEM LEAK DETECTED (SMALL LEAK), Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0447 Evaporative Emission Control Sys-
tem Vent Control Circuit Open
<Ref. to EN(H6DO)(diag)-272, DTC P0447 EVAPORATIVE EMISSION
CONTROL SYSTEM VENT CONTROL CIRCUIT OPEN, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0448 Evaporative Emission Control Sys-
tem Vent Control Circuit Shorted
<Ref. to EN(H6DO)(diag)-275, DTC P0448 EVAPORATIVE EMISSION
CONTROL SYSTEM VENT CONTROL CIRCUIT SHORTED, Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0451 Evaporative Emission Control Sys-
tem Pressure Sensor
<Ref. to EN(H6DO)(diag)-277, DTC P0451 EVAPORATIVE EMISSION
CONTROL SYSTEM PRESSURE SENSOR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0452 Evaporative Emission Control Sys-
tem Pressure Sensor Low Input
<Ref. to EN(H6DO)(diag)-279, DTC P0452 EVAPORATIVE EMISSION
CONTROL SYSTEM PRESSURE SENSOR LOW INPUT, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0453 Evaporative Emission Control Sys-
tem Pressure Sensor High Input
<Ref. to EN(H6DO)(diag)-282, DTC P0453 EVAPORATIVE EMISSION
CONTROL SYSTEM PRESSURE SENSOR HIGH INPUT, Diagnostic Proce-
dure with Diagnostic Trouble Code (DTC).>
P0456 Evaporative Emission Control Sys-
tem Leak Detected (Very Small
Leak)
<Ref. to EN(H6DO)(diag)-285, DTC P0456 EVAPORATIVE EMISSION
CONTROL SYSTEM LEAK DETECTED (VERY SMALL LEAK), Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0457 Evaporative Emission Control Sys-
tem Leak Detected (Fuel Cap Loose/
Off)
<Ref. to EN(H6DO)(diag)-287, DTC P0457 EVAPORATIVE EMISSION
CONTROL SYSTEM LEAK DETECTED (FUEL CAP LOOSE/OFF), Diag-
nostic Procedure with Diagnostic Trouble Code (DTC).>
P0458 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit Low
<Ref. to EN(H6DO)(diag)-289, DTC P0458 EVAPORATIVE EMISSION
CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT LOW, Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0459 Evaporative Emission Control Sys-
tem Purge Control Valve Circuit High
<Ref. to EN(H6DO)(diag)-291, DTC P0459 EVAPORATIVE EMISSION
CONTROL SYSTEM PURGE CONTROL VALVE CIRCUIT HIGH, Diagnostic
Procedure with Diagnostic Trouble Code (DTC).>
P0461 Fuel Level Sensor Circuit Range/Per-
for mance
<Ref. to EN(H6DO)(diag)-293, DTC P0461 FUEL LEVEL SENSOR CIR-
CUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic Trou-
ble Code (DTC).>
P0462 Fuel Level Sensor Circuit Low Input <Ref. to EN(H6DO)(diag)-293, DTC P0462 FUEL LEVEL SENSOR CIR-
CUIT LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0463 Fuel Level Sensor Circuit High Input <Ref. to EN(H6DO)(diag)-293, DTC P0463 FUEL LEVEL SENSOR CIR-
CUIT HIGH INPUT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0464 Fuel Level Sensor Circuit Intermittent <Ref. to EN(H6DO)(diag)-294, DTC P0464 FUEL LEVEL SENSOR CIR-
CUIT INTERMITTENT, Diagnostic Procedure with Diagnostic Trouble Code
(DTC).>
P0483 Cooling Fan Rationality Check <Ref. to EN(H6DO)(diag)-294, DTC P0483 COOLING FAN RATIONALITY
CHECK, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0500 Vehicle Speed Sensor <Ref. to EN(H6DO)(diag)-295, DTC P0500 VEHICLE SPEED SENSOR,
Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0506 Idle Control System RPM Lower
Than Expected
<Ref. to EN(H6DO)(diag)-296, DTC P0506 IDLE CONTROL SYSTEM RPM
LOWER THAN EXPECTED, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0507 Idle Control System RPM Higher
Than Expected
<Ref. to EN(H6DO)(diag)-297, DTC P0507 IDLE CONTROL SYSTEM RPM
HIGHER THAN EXPECTED, Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
DTC Item Reference

EN(H6DO)(diag)-77
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
18.Diagnostic Procedure with Diagnostic Trouble Code (DTC)
A: DTC P0011 INTAKE CAMSHAFT POSITION TIMING - OVER-ADVANCED
(BANK 1)
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION <Ref. to GD(H6DO)-9, DTC P0011 INTAKE CAMSHAFT POSITION TIMING
- OVER-ADVANCED (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Engine stalls.
•Erroneous idling
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-45,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-35, Inspection
Mode.>.
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC).” <Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Measure the AVCS system operating angle
and oil flow control solenoid valve duty output
using Subaru Select Monitor or general scan
tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the AVCS system operating
angle approx. 0 deg., and oil
flow control solenoid valve duty
output approx. 10%?
Check the follow-
ing item and repair
or replace if nec-
essary.
•Oil pipe (clog)
•Oil flow con-
trol solenoid
valve (clog or
dirt of oil rout-
ing, setting of
spring, clog of
valve)
•Intake cam-
shaft (dirt, dam-
age of
camshaft)
•Timing chain
(matching of
timing mark)
A temporary mal-
function. Perform
the following, and
clean the oil rout-
ing.
Replace the
engine oil and idle
the engine for 5
minutes, and then
replace the oil filter
and engine oil.

EN(H6DO)(diag)-78
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
B: DTC P0016 CRANKSHAFT POSITION - CAMSHAFT POSITION CORRELA-
TION (BANK 1)
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION <Ref. to GD(H6DO)-11, DTC P0016 CRANKSHAFT POSITION - CAMSHAFT
POSITION CORRELATION (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Engine stalls.
•Erroneous idling
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-45,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-35, Inspection
Mode.>.
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the rele-
vant DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC).” <Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Measure the AVCS system operating angle
and oil flow control solenoid valve duty output
using Subaru Select Monitor or general scan
tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the AVCS system operating
angle approx. 0 deg., and oil
flow control solenoid valve duty
output approx. 10%?
Check the follow-
ing item and repair
or replace if nec-
essary.
•Oil pipe (clog)
•Oil flow con-
trol solenoid
valve (clog or
dirt of oil rout-
ing, setting of
spring, clog of
valve)
•Intake cam-
shaft (dirt, dam-
age of
camshaft)
•Timing chain
(matching of
timing mark)
A temporary mal-
function. Perform
the following, and
clean the oil rout-
ing.
Replace the
engine oil and idle
the engine for 5
minutes, and then
replace the oil filter
and engine oil.

EN(H6DO)(diag)-79
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
C: DTC P0018 CRANKSHAFT POSITION - CAMSHAFT POSITION CORRELA-
TION (BANK 2)
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION <Ref. to GD(H6DO)-11, DTC P0018 CRANKSHAFT POSITION - CAMSHAFT
POSITION CORRELATION (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Engine stalls.
•Erroneous idling
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-45,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-35, Inspection
Mode.>.
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Check the appro-
priate DTC using
the “List of Diag-
nostic Trouble
Code (DTC)”.
<Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Check the AVCS system operating angle
and oil flow control solenoid valve duty output
using Subaru Select Monitor or general scan
tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the AVCS system operating
angle approx. 0 deg., and oil
flow control solenoid valve duty
output approx. 10%?
Check the follow-
ing item and repair
or replace if nec-
essary.
•Engine oil
(amount, dirt)
•Oil pipe (clog)
•Oil flow con-
trol solenoid
valve (clog or
dirt of oil rout-
ing, setting of
spring, clog of
valve)
•Intake cam-
shaft (dirt, dam-
age of
camshaft)
•Timing chain
(matching of
timing mark)
A temporary mal-
function. Perform
the following, and
clean the oil rout-
ing.
Replace the
engine oil and idle
the engine for 5
minutes, and then
replace the oil filter
and engine oil.

EN(H6DO)(diag)-80
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
D: DTC P0021 INTAKE CAMSHAFT POSITION TIMING - OVER-ADVANCED
(BANK 2)
DTC DETECTING CONDITION:
•Detected when two consecutive driving cycles with fault occur.
•GENERAL DESCRIPTION <Ref. to GD(H6DO)-11, DTC P0021 INTAKE CAMSHAFT POSITION TIMING
- OVER-ADVANCED (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
•Engine stalls.
•Erroneous idling
CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-45,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-35, Inspection
Mode.>.
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Check the appro-
priate DTC using
the “List of Diag-
nostic Trouble
Code (DTC)”.
<Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Check the AVCS system operating angle
and oil flow control solenoid valve duty output
using Subaru Select Monitor or general scan
tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the AVCS system operating
angle approx. 0 deg., and oil
flow control solenoid valve duty
output approx. 10%?
Check the follow-
ing item and repair
or replace if nec-
essary.
•Engine oil
(amount, dirt)
•Oil pipe (clog)
•Oil flow con-
trol solenoid
valve (clog or
dirt of oil rout-
ing, setting of
spring, clog of
valve)
•Intake cam-
shaft (dirt, dam-
age of
camshaft)
•Timing chain
(matching of
timing mark)
A temporary mal-
function. Perform
the following, and
clean the oil rout-
ing.
Replace the
engine oil and idle
the engine for 5
minutes, and then
replace the oil filter
and engine oil.

EN(H6DO)(diag)-82
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Check DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC)”. <Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK HARNESS BETWEEN ECM AND
VARIABLE VALVE LIFT DIAGNOSIS OIL
PRESSURE SWITCH CONNECTOR.
1) Idle the engine.
2) Turn the ignition switch to OFF.
3) Disconnect the connectors from ECM and
variable valve lift diagnosis oil pressure switch
connector.
4) Measure the resistance of harness
between variable valve lift diagnosis oil pres-
sure switch connector and engine ground.
Connector & terminal
(E71) No. 1 — Engine ground:
Is the resistance more than 1
MΩ?
Go to step 3.Repair the ground
short circuit of har-
ness between
ECM and variable
valve lift diagnosis
oil pressure switch
connector.
3CHECK HARNESS BETWEEN ECM AND
VARIABLE VALVE LIFT DIAGNOSIS OIL
PRESSURE SWITCH CONNECTOR.
Measure the resistance of harness between
ECM and variable valve lift diagnosis oil pres-
sure switch connector.
Connector & terminal
(B134) No. 31 — (E71) No. 1:
Is the resistance less than 1
Ω?
Replace the vari-
able valve lift diag-
nosis oil pressure
switch. <Ref. to
FU(H6DO)-26,
Va r i a bl e Va l ve L i f t
Diagnosis Oil
Pressure Switch.>
Go to step 4.
Repair the open
circuit of harness
between ECM and
variable valve lift
diagnosis oil pres-
sure switch con-
nector.
4CHECK DTC.
1) Erase the memory. <Ref. to
EN(H6DO)(diag)-45, Clear Memory Mode.>
2) Check the DTC after idling the engine.
Is DTC displayed? Replace the oil
switching solenoid
valve. <Ref. to
ME(H6DO)-78, Oil
Switching Sole-
noid Valve.> Go to
step 5.
END.
5CHECK DTC.
1) Erase the memory. <Ref. to
EN(H6DO)(diag)-45, Clear Memory Mode.>
2) Check the DTC after idling the engine.
Is DTC displayed? Check for oil rout-
ing.
Contact with SOA
Service Center.
END.

EN(H6DO)(diag)-84
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Check DTC using
“List of Diagnostic
Tr o u b l e C o d e
(DTC)”. <Ref. to
EN(H6DO)(diag)-
69, List of Diag-
nostic Trouble
Code (DTC).>
Go to step 2.
2CHECK HARNESS BETWEEN ECM AND
VARIABLE VALVE LIFT DIAGNOSIS OIL
PRESSURE SWITCH CONNECTOR.
1) Idle the engine.
2) Turn the ignition switch to OFF.
3) Disconnect the connectors from ECM and
variable valve lift diagnosis oil pressure switch
connector.
4) Measure the resistance of harness
between variable valve lift diagnosis oil pres-
sure switch connector and engine ground.
Connector & terminal
(E72) No. 1 — Engine ground:
Is the resistance more than 1
MΩ?
Go to step 3.Repair the ground
short circuit of har-
ness between
ECM and variable
valve lift diagnosis
oil pressure switch
connector.
3CHECK HARNESS BETWEEN ECM AND
VARIABLE VALVE LIFT DIAGNOSIS OIL
PRESSURE SWITCH CONNECTOR.
Measure the resistance of harness between
ECM and variable valve lift diagnosis oil pres-
sure switch connector.
Connector & terminal
(B134) No. 32 — (E72) No. 1:
Is the resistance less than 1
Ω?
Replace the vari-
able valve lift diag-
nosis oil pressure
switch. <Ref. to
FU(H6DO)-26,
Va r i a bl e Va l ve L i f t
Diagnosis Oil
Pressure Switch.>
Go to step 4.
Repair the open
circuit of harness
between ECM and
variable valve lift
diagnosis oil pres-
sure switch con-
nector.
4CHECK DTC.
1) Erase the memory. <Ref. to
EN(H6DO)(diag)-45, Clear Memory Mode.>
2) Check the DTC after idling the engine.
Is DTC displayed? Replace the oil
switching solenoid
valve. <Ref. to
ME(H6DO)-78, Oil
Switching Sole-
noid Valve.> Go to
step 5.
END.
5CHECK DTC.
1) Erase the memory. <Ref. to
EN(H6DO)(diag)-45, Clear Memory Mode.>
2) Check the DTC after idling the engine.
Is DTC displayed? Check for oil rout-
ing.
Contact with SOA
Service Center.
END.

EN(H6DO)(diag)-87
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Start and warm-up the engine.
2) Turn the ignition switch to OFF.
3) Disconnect the connectors from ECM and
front oxygen (A/F) sensor.
4) Measure the resistance of harness
between ECM and front oxygen (A/F) sensor
connector.
Connector & terminal
(B136) No. 2 — (E47) No. 1:
(B136) No. 3 — (E47) No. 1:
Is the resistance less than 1
Ω?
Go to step 2.Repair the open
circuit of harness
between ECM and
front oxygen (A/F)
sensor connector.
2CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
Measure the resistance of harness between
ECM and front oxygen (A/F) sensor connector.
Connector & terminal
(B135) No. 8 — (E47) No. 4:
(B135) No. 9 — (E47) No. 3:
Is the resistance less than 1
Ω?
Go to step 3.Repair the open
circuit of harness
between ECM and
front oxygen (A/F)
sensor connector.
3CHECK HARNESS BETWEEN MAIN RELAY
AND FRONT OXYGEN (A/F) SENSOR CON-
NECTOR.
Measure the resistance of harness between
main relay and front oxygen (A/F) sensor con-
nector.
Connector & terminal
(B47) No. 3 — (E47) No. 2:
Is the resistance less than 1
Ω?
Go to step 4.Repair the open
circuit of harness
between main
relay and front
oxygen (A/F) sen-
sor connector.
4CHECK FRONT OXYGEN (A/F) SENSOR.
Measure the resistance between front oxygen
(A/F) sensor connector terminals.
Te r m i n a l s
No. 2 — No. 1:
Is the resistance less than 5
Ω?
Go to step 5.Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H6DO)-28,
Fr o nt Ox yg en ( A /
F) Sensor.>
5CHECK POOR CONTACT.
Check poor contact of ECM and front oxygen
(A/F) sensor connector.
Is there poor contact in ECM or
front oxygen (A/F) sensor con-
nector?
Repair the poor
contact of ECM or
front oxygen (A/F)
sensor connector.
Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H6DO)-28,
Fr o nt Ox yg en ( A /
F) Sensor.>

EN(H6DO)(diag)-90
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step Check Yes No
1 CHECK POWER SUPPLY TO FRONT OXY-
GEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from front oxygen
(A/F) sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between front oxygen
(A/F) sensor connector and engine ground.
Connector & terminal
(E47) No. 2 (+) — Engine ground (–):
Is the voltage more than 10 V? Go to step 2.Repair the power
supply line.
NOTE:
In this case, repair
the following item:
•Open circuit
of harness be-
tween main re-
lay and front
oxygen (A/F)
sensor connec-
tor
•Poor contact
in front oxygen
(A/F) sensor
connector
•Poor contact
of main relay
connector
2CHECK GROUND CIRCUIT FOR ECM.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 3 — Chassis ground:
(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:
Is the resistance less than 5
Ω?
Go to step 3.Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following item:
•Open circuit
of harness be-
tween ECM and
engine ground
terminal
•Poor contact
in ECM connec-
tor
•Poor contact
of coupling con-
nector
3CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor or
general scan tool.
NOTE:•Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
•General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the current more than 0.2 A? Repair the poor
contact of connec-
tor.
NOTE:
In this case, repair
the following item:
•Poor contact
in front oxygen
(A/F) sensor
connector
•Poor contact
of coupling con-
nector
•Poor contact
in ECM connec-
tor
Go to step 4.
4CHECK OUTPUT SIGNAL OF ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B136) No. 2 (+) — Chassis ground (–):
(B136) No. 3 (+) — Chassis ground (–):
Is the voltage less than 1 V? Go to step 6.Go to step 5.