P0505
Idle Control System Malfunction
This code means your car's computer has detected a problem with the system that controls your engine's idle speed. This system ensures your engine runs smoothly when your foot isn't on the gas pedal.
Idle Control System Malfunction
Common causes
- high
Faulty Idle Air Control (IAC) Valve
The IAC valve can become clogged with carbon or fail electronically, preventing it from regulating idle speed.
Typical part cost: $50-200 part
- medium
Vacuum Leaks
Leaking vacuum hoses, intake manifold gaskets, or PCV system components can introduce unmetered air, disrupting idle.
Typical part cost: $0-100 for repair
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First things to check
- 1Inspect the IAC valve and throttle body for carbon buildup and clean if necessary.
- 2Check all vacuum lines and intake manifold gaskets for leaks using a smoke machine or by listening for hissing sounds.
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Related codes
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Frequently asked questions
What is an IAC valve?
The Idle Air Control (IAC) valve is an electronically controlled valve that regulates the amount of air bypassing the closed throttle plate, thereby controlling the engine's idle speed.
Can a P0505 code cause my car to stall?
Yes, a malfunctioning idle control system, often due to a faulty IAC valve or vacuum leak, can lead to an unstable idle speed, causing the engine to stall, especially when you come to a stop.
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