Subaru IMPREZA GD 2007 Series Manual page 383

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
7 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is higher than 75°C
(167°F).
2) For AT models, set the select lever to the "P"
or "N" range, and for MT models, place the shift
lever in the neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of mass air flow and intake air
temperature sensor signal 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(H4SO)(diag)-32, Subaru Select Monitor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
8 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is higher than 75°C
(167°F).
2) For AT models, set the select lever to the "P"
or "N" range, and for MT models, place the shift
lever in the neutral position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Open the front hood.
6) Measure the ambient temperature.
7) Read the data of mass air flow and intake air
temperature sensor signal 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(H4SO)(diag)-32, Subaru Select Monitor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
9 CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between the ECM and
chassis ground for faulty cylinders.
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 (–):
Check
Is the measured value 2.0 —
5.0 g/s (0.2 — 0.53 lb/m)?
Subtract ambient temperature
from intake air temperature. Is
the obtained value –10 — 50°C
(–18 — 90°F)?
Is the voltage 10 V or more?
EN(H4SO)(diag)-274
Yes No
Go to step 8. Replace the mass
air flow and intake
air temperature
sensor. <Ref. to
FU(H4SO)-28,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Go to step 9. Check the mass air
flow and intake air
temperature sen-
sor. <Ref. to
FU(H4SO)-28,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
Go to step 14. Go to step 10.