P0506
Idle Control System RPM - Lower Than Expected
Idle / air control
Generic OBD-II
High
What it means
P0506 means the engine is idling slower than the ECM's target speed. The most common cause is a carbon-fouled throttle body or a sticking idle air control valve restricting the air the engine needs at idle. A low idle can make the engine feel rough and, at worst, stall when you come to a stop — so it is worth fixing promptly.
High
Can I keep driving? Drivable but frustrating and risky — the engine may stall at stops or idle, so fix it promptly to avoid being stranded.
Common symptoms
What you'll notice
- Idle speed lower than normal
- Engine stalls, especially when stopping or coasting to a stop
- Rough or unstable idle
- Check-engine light on
Common causes
Most likely first
- Carbon-fouled or dirty throttle body restricting idle airflowLikely
- Faulty or sticking idle air control (IAC) valveCommon
- Vacuum or intake restriction affecting idle airCommon
- Dirty or faulty mass airflow sensor giving a wrong readingLess often
- Wiring fault in the idle control circuitLess often
How to diagnose & fix
Work through it in order
- Clean the throttle body and idle air passages — the most common fix.
- Inspect, clean, or replace the idle air control valve if fitted.
- Check for intake restrictions and confirm the throttle plate closes/opens correctly.
- Inspect the MAF sensor and idle-circuit wiring, then relearn idle, clear, and re-test.
FAQ
Quick answers
Is it safe to drive with P0506?+
It is drivable, but a low idle can cause stalling at stops, which is unsafe in traffic. Fix it promptly.
Can I just clear P0506?+
You can, and some cars need an idle relearn after cleaning, but the code returns if the throttle body, IAC, or airflow problem is not corrected.
Related codes
Often seen with P0506
Read & clear P0506 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX