DTC P0505: Idle Control System Malfunction: Condition

DTC is set when actual engine speed is excessively higher or lower than target speed preset in PCM for more than 14 seconds. Possible causes are:

• Idle Air Control (IAC) valve malfunction.
• Leakage in intake air system.
• Open or short circuit between terminal "A" on IAC valve and main relay.
• Open or short circuit between terminal "B" on IAC valve and terminal No. 4Q on Powertrain Control Module (PCM).