Subaru Impreza 2003 Service Manual page 1325

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
7 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 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 OBD-II general scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4DOTC)-32, Subaru Select Mon-
itor.>
•OBD-II general scan tool
For detailed operation procedure, refer to the
OBD-II General Scan Tool Instruction Manual.
Check
Subtract ambient temperature
from intake air temperature.
Is the obtained value −10°C —
50°C (14°F — 122°F)?
EN(H4DOTC)-149
ENGINE (DIAGNOSTICS)
Yes
Contact your Sub- Check the mass
aru distributor ser- air flow and intake
vice. air temperature
sensor. <Ref. to
NOTE:
FU(H4DOTC)-34,
Inspection by DTM
Mass Air Flow and
is required, be-
Intake Air Temper-
cause probable
ature Sensor.>
cause is deteriora-
tion of multiple
parts.
No