Subaru 2006 Legacy, Manual

Page: 1193 / 4302

EN(H4SO U5)(diag)-2 88
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
13 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in 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 procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO U5)(diag)-27, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the measured value 2.1 —
3.4 g/s (0.28 — 0.45 lb/m)? Go to step
14
. Replace the mass
air flow and intake
air temperature
sensor. <Ref. to
FU(H4SO)-25,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
14 CHECK MASS AIR FLOW AND INTAKE AIR
TEMPERATURE SENSOR.
1) Start the engine and warm-up engine until
coolant temperature is greater than 60°C
(140°F).
2) Place the shift lever in 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 procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO U5)(diag)-27, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Subtract ambient temperature
from intake air temperature. Is
the obtained value –10 — 50°C
(–18 — 90°F)? Go to step
15
. Check the mass
air flow and intake
air temperature
sensor. <Ref. to
FU(H4SO)-25,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>
15 CHECK REAR OXYGEN SENSOR DATA.
1) Warm-up the engine until engine coolant
temperature is above 70°C (158°F), and keep
the engine speed at 3,000 rpm. (Max. 2 min-
utes)
2) Read the data of rear oxygen sensor signal
using Subaru Select Monitor or general scan
tool.
NOTE:
• For MT model, depress the clutch pedal.
• Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO U5)(diag)-27, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Is the voltage 490 mV or
more? Go to step
19
. Go to step
16
.
Step Check Yes No
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