Parts
$0–150
P0506 — Idle Speed Lower Than Expected
CAUTIONIs it safe to drive? The engine idles too low and may stall. Driveable but annoying and can leave you stalled at a light.
What P0506 means
Actual idle RPM is below the computer's target. Usually airflow at idle is restricted or the throttle body is dirty.
Most likely causes (in order)
- Dirty throttle body / carbon on the plate
- Vacuum leak affecting idle control
- Faulty idle air control (older engines)
- Throttle body needs a relearn after cleaning
Symptoms you might notice
- Low / stalling idle
- Stumble at stops
What to check first
Clean the throttle body, then perform an idle/throttle relearn (Techstream/scan tool on Toyota). Check for vacuum leaks.
Repair cost & difficulty
Labor
0.5–1.5 hr
Difficulty
DIY-friendly