Subaru 2009 IMPREZA Service Manual page 1486

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK SECONDARY AIR COMBINATION
VALVE.
1) Remove the secondary air combination
valve. <Ref. to EC(H4DOTC)-25, Secondary Air
Combination Valve.>
2) Blow in air from the secondary air combina-
tion valve air inlet, and check whether there are
leaks at the pipe connections.
Check
Are there air leaks from the pipe
connections?
EN(H4DOTC)(diag)-265
ENGINE (DIAGNOSTICS)
Yes No
Replace the sec- Even if DTC is
ondary air combi- detected, the cir-
nation valve on the cuit has returned to
side with the air a normal condition
leak. <Ref. to at this time. Repro-
EC(H4DOTC)-25, duce the failure,
Secondary Air and then perform
Combination the diagnosis
Valve.> again.
NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.