Subaru 2009 IMPREZA Service Manual page 1339

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK ENGINE COOLANT TEMPERA-
TURE.
1) Start the engine and warm up completely.
2) Measure the engine coolant temperature
using the 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(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Check
Is the engine coolant tempera-
ture 75°C (167°F) or higher?
EN(H4DOTC)(diag)-118
Yes No
Replace the mass Check DTC P0125
air flow and intake using "List of Diag-
air temperature nostic Trouble Code
sensor. <Ref. to (DTC)". <Ref. to
FU(H4DOTC)-39, EN(H4DOTC)(diag)
Mass Air Flow and -83, List of Diagnos-
Intake Air Temper- tic Trouble Code
ature Sensor.> (DTC).>