P0505: Idle Air Control System Malfunction
6 vehicles · 4 makes
P0505 is an OBD-II diagnostic trouble code meaning “Idle Air Control System Malfunction.” The idle air control (IAC) system is not maintaining proper idle speed. Engine may idle too high or too low. This code appears across 6 vehicle models from 4 manufacturers.
Common Causes
Diagnostic Tools
To diagnose P0505, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (6)
FAQ
What does P0505 mean?
P0505 stands for "Idle Air Control System Malfunction." The idle air control (IAC) system is not maintaining proper idle speed. Engine may idle too high or too low.
What are the most common causes of P0505?
The most common causes of P0505 are: Faulty IAC valve, Carbon buildup in IAC passages, Vacuum leak, Throttle body carbon buildup, Electrical fault in IAC circuit. The specific cause varies by vehicle.
How much does it cost to fix P0505?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0505?
Au7o has documented P0505 across 6 vehicle models from 4 manufacturers: Cadillac, Ford, Nissan, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.