P0505 Idle Control System Malfunction
What does P0505 mean?
P0505 — Idle Control System Malfunction. This is an OBD-II diagnostic trouble code a scanner retrieves when your vehicle's computer detects idle control system malfunction. The level of risk depends on how the vehicle is currently running and how long you've been driving with the light on.
Common causes of P0505
- Carboned-up or faulty idle air control (IAC) valve
- Vacuum leaks in the intake system
- Throttle body dirty or sticking
- Faulty throttle position or MAF sensor
- Wiring or connector issues to the IAC
How to fix P0505
- Clean the idle air control valve and throttle body
- Smoke test for vacuum leaks
- Watch commanded vs actual idle RPM on an OBD-II scanner
- Check IAC wiring and connector
- Replace the IAC valve if it will not control idle