OBD-II code · Powertrain (generic)
P0506 Idle Air Control System RPM Lower Than Expected
The engine idles below the target RPM despite the IAC opening fully. Indicates restricted air path past the IAC — typically a heavily fouled throttle body or stuck IAC valve.
Is it safe to drive with P0506?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyThrottle body or idle bypass passage clogged
- PossibleIAC valve stuck mostly closed
Symptoms
- Check engine light on
- Idle speed too high, too low, or unstable
- Possible stalling at idle or after cold start
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Idle Air Control Valve, Throttle Body
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.