DTC P0505: Idle Control System Malfunction: Condition

DTC is set when closed signal to Idle Air Control (IAC) is not detected with engine running. This is a continuous monitor. MIL is illuminated when Engine Control Module (ECM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Short or open circuit between main relay, IAC valve and ECM.
• IAC valve malfunction.
• ECM malfunction.