Subaru Legacy 2004 Service Manual page 866

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
5 CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.
Connector & terminal
(B3) No. 4 (+) — Engine ground (
6 CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between mass air flow and intake air tempera-
ture sensor connector and engine ground.
Connector & terminal
(B3) No. 5 — Engine ground:
Check
Is the voltage more than 3 V?
"
):
Is the resistance less than 5
!?
EN(H4SO 2.5)(diag)-107
ENGINE (DIAGNOSTICS)
Yes
Go to step 6. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector
• Poor contact in
mass air flow and
intake air tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
coupling connector
• Poor contact in
joint connector
Replace the mass Repair the har-
air flow and intake ness and connec-
air temperature tor.
sensor. <Ref. to
NOTE:
FU(H4SO 2.5)-26,
In this case, repair
Mass Air Flow and
the following:
Intake Air Temper-
• Open circuit in
ature Sensor.>
harness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector
• Poor contact in
mass air flow and
intake air tempera-
ture sensor
• Poor contact in
ECM
• Poor contact in
joint connector
No