Subaru 2009 IMPREZA Service Manual page 896

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
CQ:DTC P1493 EGR SOLENOID VALVE SIGNAL #1 CIRCUIT MALFUNCTION
(HIGH INPUT)
1. OUTLINE OF DIAGNOSIS
• Detects open or short circuit of EGR.
• Judge as NG when the ECM output level differs from the actual terminal level.
2. COMPONENT DESCRIPTION
(1)
(2)
(1) Engine control module (ECM)
(2) Computer unit (CPU)
3. ENABLE CONDITIONS
Secondary Parameters
Elapsed time after starting the engine
EGR valve target position
Battery voltage
4. GENERAL DRIVING CYCLE
Always perform the diagnosis continuously.
(3)
(4)
(3) Detecting circuit
(4) Switch circuit
Enable Condition
1 second
> 0 step
10.9 V
GD(H4SO)-172
(5)
(6)
(5) Battery voltage
(6) Main relay
EN-02051