P0506 Code: Idle Air Control System RPM Lower Than Expected
🟠 Moderate severity · drivable
Drivable, but the idle is too low and may stall, especially when stopping.
What P0506 means
The engine is idling slower than the computer expects. The idle air control system isn't letting in enough air at idle, so the engine may struggle or stall.
Symptoms
- Check engine light is on
- Low or rough idle
- Engine stalling when stopping
- Shaking at idle
Common causes
- most common: Dirty or faulty idle air control (IAC) valve
- common: Dirty throttle body
- common: Vacuum leak
- less common: Faulty throttle position sensor
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Clean the idle air control valve and throttle body | Yes | $10–40 |
| Replace a faulty idle air control valve | Yes | $50–200 |
| Find and repair vacuum leaks | Yes | $10–100 |
Frequently asked questions
Can I drive with a P0506 code?
Yes, but the engine may stall at stops. Fix it soon.
What is the most common cause of P0506?
A dirty or faulty idle air control valve.
How much does it cost to fix a P0506?
$10–$40 for cleaning, or $50–$200 for a new idle air control valve.
Related codes
P0505
P0505 Code: Idle Control System Malfunction
P0507P0507 Code: Idle Air Control System RPM Higher Than Expected
P0171P0171 Code: System Too Lean (Bank 1)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.