P0506: Idle air control system RPM lower than expected
Drive carefully. Get it checked within a week or two.
Can I drive with P0506?
Yes, but drive carefully and get it checked soon. Idle is abnormally low and vibrating, risking stalling when putting into drive or using A/C.
What does P0506 mean?
P0506 stands for Idle Air Control System RPM Lower Than Expected.
Symptoms you may notice
- Engine stalls when coming to a stop or shifting into reverse
- Engine idles excessively high (over 1200 RPM) or surges up and down
- Heavy vibration through the steering wheel at idle
How much does it cost to fix?
Repair costs for code P0506 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- Heavy carbon deposits choking the throttle plate or IAC
- Failed or sticking IAC motor
- Excessive electrical or A/C compressor mechanical drag
- Restricted air intake filter
What to do next
- Remove the intake tube and clean all carbon buildup from the throttle plate edge.
- Perform an idle air volume relearn procedure.
- Test IAC motor resistance and movement.
Last updated: October 2026
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General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code P0506 means the engine idle speed is 100 to 200 RPM below target. The vehicle will shudder and vibrate heavily when stopped in gear. Cleaning the black varnish out of the throttle body bore solves this code in over 70% of cases without buying any parts.