DTC P0506: Idle Control System Rpm Lower Than Expected - IMPREZA 2.2L, Legacy & Outback 2.5L M/T & Outback Sport

Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE . If DTC P0505 and/or P1505 exist, diagnose and repair those DTCs. Do not diagnose DTC P0506. If DTC P0506 is only DTC set, go to next step.
Turn ignition off. Remove IAC solenoid valve from throttle body. Using an air gun, force air into IAC solenoid valve air by-pass inlet. Ensure air escapes from both main air passage and assist air passage. If air escapes from both passages, go to step 4. If air does not escape from both passages, replace IAC solenoid valve, then go to next step.
Start and warm engine. Turn all accessories off. Using scan tool, observe IAC solenoid valve duty ratio. If duty cycle is more than 60 percent, go to next step. If duty cycle is not more than 60 percent, test is complete.
Turn ignition off. Remove IAC solenoid valve. Remove throttle body. Ensure no foreign materials are stuck in air by-pass line. Using air gun, force air into IAC solenoid valve installation area and throttle valve interior. If air escapes from both areas, replace IAC solenoid valve. If air does not escape, replace throttle body. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES and VERIFICATION PROCEDURE .