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Hello and welcome to just answer and allowing me to assist you. I have two separate diagnostic trouble codes for #14.(P1508) Idle Air Control Valve Circuit FailureProbable causes*IAC valve*IAC valve circuit*ECU(P0505) Idle Control System MalfunctionProbable causes*IAC valve mechanical malfunction*Fast Idle thermo valve malfunction (A/T)*Throttle body clogged port, improper adjustment*Intake manifold, gasket leakage*Vacuum hoses leakage*Engine Coolant Temperature sensor incorrect output*Throttle Position sensor incorrect outputI assume you don't have a scantool so here's some other troubleshooting tips.Check the engine speed at idle with no load conditions: (headlights, blower fan, rear defogger, radiator fan, and air conditioning are not operating.)Is it 750 plus or minus 50 rpm or is it around 550 rpm? (B18B)If it's 750 plus or minus 50 then it's an intermittent failure. Reset the ECU if this is the case.Another thing you could try is to disconnect the 2P connector from the IAC valve. Does the engine speed drop or the engine stall? If not replace the IAC valve. See if you can clean the ports in the throttle body. hope this helps your situation.