P0505: Idle Air Control System Malfunction
The engine computer can't control idle speed properly.
Green, yellow, red: three ways P0505 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Idle a little off.
Schedule a repair
Surging or low idle. Clean or repair soon.
Stop and get help
Stalling at intersections. Don't drive until fixed.
Symptoms you might notice
- Idle too high or too low
- Stalling at stops
Common causes, cheapest first
- Dirty throttle body or idle air valve
- Vacuum leak
- Failed idle air control valve
What you can check before calling
- Notice whether idle surges
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More idle, speed & electrical codes
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0505 mean?
P0505 means "Idle Air Control System Malfunction". The engine computer can't control idle speed properly.
Can I drive with code P0505?
It depends on what the vehicle is doing. Green: Idle a little off. Yellow: Surging or low idle. Clean or repair soon. Red: Stalling at intersections. Don't drive until fixed.
What causes P0505?
The most common causes are: dirty throttle body or idle air valve; vacuum leak; failed idle air control valve.
Is P0505 a serious code?
It can be. Stalling at intersections. Don't drive until fixed.
Skip the shop. We'll come to you.
Book online in about a minute, or call or text the office. We'll confirm the details and get a mechanic headed your way.