Question

What does code P0505 mean?

Engine code P0505 means “Idle Control System,” indicating a defective idle air control (IAC) system.

In older cars, the IAC is located on or close to the throttle body. The IAC regulates your car’s idle speed, measuring the amount of air passing through the throttle plate’s throat. The throttle plate closes when your car idles, decreasing the amount of air reaching the engine. Then, the powertrain control module (PCM) permits the car to maintain its idling speed by opening the bypass air channel.

The PCM logs this error code when there’s an issue with the IAC’s response, like a general problem or a problem with the car’s RPM being lower or higher than what the car expects.

What are the symptoms of a P0505 code?

The most obvious symptom is an illuminated check engine light. The following are some other symptoms you can observe when this code activates.

• The engine stalls while idling
• Low or high idle speed
• Issue starting your car
• Irregular idle speed

What can cause a P0505 code?

These are some of the main reasons why the code shows up in your car.

• Defective idle air control (IAC) valve
• Vacuum leakage
• Broken wires or poor connections
• Idle speed is out of calibration
• Faulty PCM

How to fix code P0505

These are some steps to fix this engine error code.

• If defective or dirty, clean or change the idle air control valve.
• Repair or change the faulty vacuum hoses or intake parts.
• If broken or corroded, repair or replace the wiring or connectors.
• Reprogram or change the PCM if it is faulty.
• Then, clear the code and test drive the car to ensure there are no signs of the code.

Can you drive with a P0505 code?

Though you can technically drive with this error code, we don’t recommend it. The error code can cause engine stalling, irregular idling, and a decrease in engine performance, possibly causing dangerous driving conditions. Code P0505 repair cost can start at $50 and can go up to or more than $1,000 based on the type of repair.