Subaru 2009 IMPREZA Service Manual page 1329

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?
Check
EN(H4DOTC)(diag)-108
Yes No
Check the appropri- Replace the mass
ate DTC using the air flow and intake
"List of Diagnostic air temperature
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).>